for first-wave boomers born from 1946 to 1950, because last-wave boomers are more likely to have their DB pensions frozen with relatively little job tenure." The percentage of workers covered by a traditional defined benefit (DB) pension plan declined steadily from 38% in 1980 to 20% in 2008. In contrast, the percentage of workers covered by a defined contribution (DC) pension plan has been increasing over time. From 1980 through 2008, the proportion of private wage and salary workers participating in only DC pension plans increased from 8% to 31%. Most of the shift has been the private sector, which few changes in the public sector. Some experts expect that most private-sector plans will be frozen in the next few years and eventually terminated. Under the typical DB plan freeze, current participants will receive retirement benefits based on their accruals up to the date of the freeze, but will not accumulate any additional benefits; new employees will not be covered. Instead, employers will either establish new DC plans or increase contributions to existing DC plans. Employees in unions are more likely to be covered by a defined benefit plan, with 67% of union workers covered by such a plan during 2011 versus 13% of non-union workers. Economist Paul Krugman wrote in November 2013: "Today, however, workers who have any retirement plan at all generally have defined-contribution plans—basically, 401(k)'s—in which employers put money into a tax-sheltered account that's supposed to end up big enough to retire on. The trouble is that at this point it's clear that the shift to 401(k)'s was a gigantic failure. Employers took advantage of the switch to surreptitiously cut benefits; investment returns have been far lower than workers were told to expect; and, to be fair, many people haven't managed their money wisely. As a result, we're looking at a looming retirement crisis, with tens of millions of Americans facing a sharp decline in living standards at the end of their working lives. For many, the only thing protecting them from abject penury will be Social Security." A 2014 Gallup poll indicated that 21% of investors had either taken an early withdrawal of their 401(k) defined contribution retirement plan or a loan against it over the previous five years; while both options are possible, they are not the intended purpose of 401k plans and can have substantial costs in taxes, fees and a smaller retirement fund.