By Jeff Cox, May 20, 2015, CNBC

At a time when 8.5 million Americans still don't have jobs, some 40 percent have given up even looking.

The revelation, contained in a new survey Wednesday showing how much work needs to be done yet in the U.S. labor market, comes as the labor force participation rate remains mired near 37-year lows.

A tight jobs market, the skills gap between what employers want and what prospective employees have to offer, and a benefits program that, while curtailed from its recession level, still remains obliging have combined to keep workers on the sidelines, according to a Harris poll of 1,553 working-age Americans conducted for Express Employment Professionals.

On the bright side, the number is actually better than 2014, the survey's inaugural year, when 47 percent of the jobless said they had given up.