Despite hunger strikes, marches and mine occupations by the highly organised and militant miners' federation, the number at work has inexorably shrunk to under 2, 000, as one mine after another has closed.

ECONOMIST: Bolivia

Most countries use similar standards, but in areas such as IT, some extra work was needed to make sure that the occupations were being properly grouped and understood.

BBC: How it's worked out

As with other lucrative blue-collar occupations, these trades take training, but they promise steady work and better-than-average wages.

FORBES: Magazine Article

Factor in the migration of skilled labor from mid-wage occupations to lower-paying ones, and many skilled workers are unable to find decent and relevant work.

FORBES: Is Minimum Wage Fair?

The report, compiled using information from the Labor Department, state agencies, news articles and trade and professional associations, finds that California is the most regulated place to work, requiring licenses in at least 177 occupations.

FORBES: Worker's Permit