Surprising that Germany is not on here. What gives?

Without cost of living/GDP info, this chart is not very helpful. You could also put in Third World countries where one lives from $2 a day, if you put in Bulgaria and Luxembourg in the same chart.

Does the minimum wage enables some sort of minimum existence (however that vague idea is defined) in that country? What does minimum wage include? In the UK, it is very likely to include NHS; in the US - it wouldn't include health insurance. How many hours a week are considered a standard work-week in France, and how many in the US? How many people (in percentage) have to live off these wages? Getting back to the notoriously "lazy" French, how many days of vacation and/or sick-days could a minimum-wage worker expect? How many in the US? Could minimum wage workers get assistance with child-care (in the form of public or heavily subsidised daycare for infants or toddlers; in the form of full-day schools or public care during school vacations) that would enable them to work? Do minimum-wage workers who have had a baby get a paid "maternity/parental leave"?

Minimum wages by themselves tell us nothing. If it is impossible to live in Luxembourg even from $20/hour and those who have to work with $15/hour cannot live from it. It is impossible to say if someone who works in minimum wage in the US has almost no vacation days or days to spend with their family; or if $3/hour makes you a king in Bulgaria and so on.

Re: Spain, my translation of the relevant paragraph of the article on Salario mínimo in the Spanish Wikipedia:

In Spain, the Salario mínimo interprofessional (SMI) is the minimum lawful salary that a worker can earn independently of the job type. It is expressed in monetary units per day, month or year of work. It is annually published in the BOE [Boletín Oficial del Estado, the official publication of the government].

To establish each SMI for the year, the IPC [índice de precios al consumo, a measure of the increment of prices in basic utilities, food, etc due to inflation], the average national productivity, the increment in participation of work in the national revenue and the general situation of the economy are considered. It may be increased every six months if there are changes on the IPC estimates.

On 2011, the salario mínimo is 21,39 €/día, 641,40 €/mes and 8.981,84 €/año (14 yearly payments).

According to the professional category and the diverse collective bargainings, the amount may be increased or reduced if the worker is under certain categories of formative contracts [e.g. apprenticeship, internship, and so on]. Worker relationships and details are collected in the Estatuto de los trabajadores [workers' statutes].

It must be noted that the Spanish salario mínimo is collected by a 0.8% of the citizens, the lowest rate in the European Union, due to it being a minimum salary far lower than real mean salaries.

For more information and historical figures, there's this annex to the article.

I'm not sure what the legal minimum wage is in Greece, it may well be over 6 dollars an hour, but in reality, minimum wage is 2.50-3.00 euros (about 4 dollars) an hour. The chart above doesn't make it clear whether these are the countries' official minimum wage fees; there is often a discrepancy between the law and what actually happens in everyday practice.

Unfortunately, charts such as these have a hard time staying timely due to currency fluctuations. For example, Ireland is shown as having a minimum wage higher than $12 per hour. Yet, Ireland's minimum wage is 7.65 euros (it has been cut as part of Ireland's IMF/EU debt bailout) which only translates to about $11.04 as of today. Definitely not the >$12 as shown in the graph. Something to be aware of when looking at the graph - despite only being ~2 months old, it's already out of date.

I would also keep my eye on Portugal. Their bailout package will probably be in the ~$80 billion range from what I have read. I have a hard time seeing Portugal taking on such a massive 3-year loan, while it still has other long-term debt it still needs to restructure, without cutting the minimum wage or public benefits to make due.

It's interesting that there are no minimum wage laws in certain European countries. Does anyone know how they ensure that workers get paid fairly?

It might be more illuminating to include in the comparison the associated figures for the percentage of the country's population that is living in poverty. The link after the table is where I got the Poverty data from.
Apparently Bulgaria and the United Kingdom have similar percentages of their populations living in poverty, even though their country's stated minimum wages are quite different.

Minimum Wage/Hr Percent of Population Living in Poverty
Ireland $12 7%
France $12 6.2%
United Kingdom $10 14%
United States $7 12%
Bulgaria $1 14%

See:
http://www.nationmaster.com/graph/eco_pop_bel_pov_lin-economy-population-below-poverty-line

An interesting bit of companion data would be a % of jobs in each of these countries that pay at or near the statutory minimum wage, along with an estimate of the number of jobs / job types which are exempted. (Waiting tables in the US comes to mind.) It seems to me that in the US at least, even the classic low-wage job, flipping burgers at Mickey D's, doesn't pay minimum wage for very long before you get a promotion and start doing mariginally better. I think a ton of jobs, however, frequently end up at some magical Min. wage + $2/ hr level.

RE: Denmark not being included on this chart. Denmark actually has the highest minimum wage in the world.

"The law does not mandate a national minimum wage; minimum wages are negotiated between unions and employer associations. According to statistics released on March 1, the average minimum wage for all private and public sector collective bargaining agreements was 103.15 kroner ($20) per hour, exclusive of pension benefits. The wage provided a decent standard of living for a worker and family. Migrant workers are also entitled to minimum wage and must also adhere to the same employment regulations as Danes."

source: http://www.state.gov/g/drl/rls/hrrpt/2009/eur/136028.htm

I definitely agree that these statistics tell us nothing by themselves, if we do not know the employment rates, social welfare rates, and cost of living.

Certainly, by minimum wage statistics, the Republic of Ireland sounds like one of the best places on Earth, but I can tell you that, from here, a minimum wage doesn't pay for much. The medical system is a shambles and relies on employed individuals seeing a private GP for 60€ a visit, for example, and in stuff like rent and food costs, Ireland is way more expensive than many other European countries.

So America is already like Greece?!

Whoops, that one's not legible. Let's try again.