Yet it was agreed that the main focus of greening jobs and skills should be within existing occupations.

UNESCO: Education

Over the past three decades, the American workforce has seen a widening gap between wages for high and low-skilled occupations and a hollowing out middle-wage jobs, say New York Fed Economists.

FORBES: Wages Becoming Increasingly Polarized, Economists Confirm

Reducing the dropout rate of women in STEM careers is especially important because women in STEM jobs earn 33 percent more than those in non-STEM occupations and the wage gap between men and women in STEM jobs is smaller than in other fields.

WHITEHOUSE: First Lady Michelle Obama at the National Science Foundation Family-Friendly Policy Rollout | The White House

And we have also raised the skills level so it is only open to graduate-level occupations - and excludes other jobs like careworkers and cooks.

BBC: In full: David Cameron immigration speech

Middle-skill jobs have declined as a share of occupations across Europe as well, and inequality has increased, though not as much as in America.

ECONOMIST: The middle-class task- force

The number of jobs for engineers, technicians, scientists and those in the computer and math occupations grew by 19.5% from 2001 to 2013 in the D.

WSJ: Washington, D.C.: The New Boomtown

The majority of military jobs have direct civilian counterparts, and 81% of military careers are in non-combat occupations.

CENTERFORSECURITYPOLICY: Military service benefits civilian life

The Pew report also has some interesting information about the most common jobs held by those with college diplomas versus those who only graduated high school and it breaks down the occupations by gender.

FORBES: It Still Pays To Get A College Degree