Republican presidential candidate, businessman Donald Trump speaks to supporters during a primary night rally, Tuesday, Feb. 9, 2016, in Manchester, N.H. At his side are his wife Melania Trump, left, and daughter Ivanka Trump, right. [Photo/IC]

"My daughter has a business degree, but she has to do three jobs to keep her lower middle class life. I had the same degree as hers, but my life was much easier when I was at her age," he said.

Marty Ellsworth, born and raised in Georgetown of Washington DC, is a part-time salesman at a Ralph Lauren clothing store near his home.

"It's easy to find a job like waiters and bar tenders, but a better-paying work will be difficult to find if without a degree," he said.

When the labor market seems near "full employment", it could point to higher wages and rising inflation.

However, for years US wage earners have barely seen their incomes grow, while inflation is far below the Federal Reserve's two percent target.

Economists at Standard & Poor said, taken the broader unemployment measures into account as they called it "U-6", which includes the official unemployed, discouraged workers and part-timers who'd like full-time jobs, the unemployment rate is 9.9 percent now.

Democratic candidate Bernie Sanders also argued that the real unemployment rate for Americans is over ten percent if people forced to work part time were counted as the unemployed.

To tackle the stagnant wage increase and the still underutilized job market, Democratic candidates turn to raising minimum wage and cutting taxes for the working middle class.

Republican candidates vow to improve international trade deals and bring the outsourced jobs back to America. However, they have not offered any detailed plans except for sketches and slogans.