It found that more than a third will reach the top 5 percent and 70 percent will reach the top 20th percentile.  "Rather than static groups that experience continual high levels of income attainment, there would appear to be more fluid movement into and out of these income levels," the study says.  Read MoreThe rich dogs of Instagram  Along with more Americans climbing into the 1 percent, a surprising number fall out. Only 0.6 percent of Americans remain part of the top 1 percent for 10 years.  "Only a few persist at this elite level," the report said.  The same is true for the super rich. A separate Internal Revenue Service study of the Fortune 400, or top earning 400 Americans who made at least $139 million in 2012, found that three-quarters of them only appeared on the list for one year between 1992 and 2012. Fewer than 10 percent of them were on the list for five years or more.  Read MoreGriffin divorce reveals lavish life  Hirschl said the findings show that American incomes are highly variable, soaring for a year or two because of a job change, bonus, big sales year or deal, and sometimes crashing due to a financial shock or change.  "People bounce around like crazy with incomes," Hirschl said. He said, for instance, that one of his relatives sells cars and trucks for a living. "Some years he'll have a great year and sell a lot of cars, and make a lot more than I do," Hirschl said. "And some years he'll make and sell a lot less. A lot of people's incomes vary from year to year. It's a trade-off in our society being so market driven."
If you think America's top 1 percent earners are a static group, think again. One percenters are actually highly fluid group, research shows.