More and more of us are working as freelancers, and that translates into more and more of us worrying about job security.

The number of job categories populated mostly by independent contractors soared to 32 million, or 18 percent of all jobs, in 2014 from 20 million in 2001, according to Economic Modeling Specialists, a labor research firm, The New York Times reports.

As for the increased worry, a Gallup poll last year showed that 23 percent of Americans were concerned that their work hours would be pared up from the low to mid-teens percent in the years before the 2007-09 recession.

“In the past, firms overstaffed and offered workers stable hours,” Susan Houseman, a labor economist at the Upjohn Institute for Employment Research, told The Times. “All of these new staffing models mean shifting risk onto workers, making work less secure.”

The upshot of all this is a “transformation that promises new efficiencies and greater flexibility for ‘employers’ and ‘employees’ alike, but which threatens to undermine the very foundation upon which middle-class America was built,” venture capitalist Nick Hanauer and labor leader David Rolf write in Democracy Journal.

The employment insecurity may help explain why Americans' sentiment toward the economy soured overall in the second quarter, but the wealthy were much more optimistic, according to the CNBC All-America Economic Survey.

Only 24 percent of respondents view the economy as excellent or good, down from 27 percent in the first quarter. In terms of their outlook on the economy for the next year, again just 24 percent of respondents think the economy will get better, compared to 28 percent in the first quarter.

But among those with annual income of at least $100,000 or with at least $50,000 in the stock market, 45 percent see the economy as excellent or good, up from 33 percent in the first quarter.

The poll also showed concern about income inequality, according to CNBC, although it didn't cite specific numbers.

The survey "demonstrates that those at the top are doing great — everyone else is stagnating or faltering," Jay Campbell, who worked on the bipartisan poll with Democratic-leaning Hart Research Associates, told CNBC. "Whichever party shows it can remedy this situation is the party that will "win the economy."

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