"[F]orty-three percent of consistent Roth IRA investors contributed to their Roth IRAs between tax year 2008 and tax year 2012, and more than three-quarters of them contributed in multiple years.... Withdrawal rates rose slightly between 2008 and 2012, but still only a very small fraction of Roth IRA investors took money out of their Roth IRAs.... On average, in recent years, nearly $20 billion of contributions flowed into Roth IRAs per year. In tax year 2012, 30.3 percent of Roth IRA investors aged 18 or older contributed to their Roth IRAs, and more than four in 10 of these contributors did so at the legal limit."