The bottom 50% of income owners have no gains in income between 19 80 and 20 14. The social security data that are used to study these questions, where you can follow people over time, are very clear on that daselodectry of persistence in income over time. More generally, thereis no indication that there's a lot of mobility in or out of the bottom 50 %. There's no indication that peopl in the bottom 50%) are very likely to er move, say, to the top ten%. Are latteb, to thetop one percent? We know we need more research on that question.