Moving up the economic ladder... in the USA
National Public Radio aired a piece recently about economic research on mobility--moving from the lowest economic rung to the top run--and the results suggest mobility has not changed in two decades.
The researchers used IRS data, which, apparently, is not too often granted by the tax agency.
It has always been difficult to move up in the United States; however, it's more difficult to move up in the U.S. than in other developed countries.
There are caveats as well: depending on your school segregation issues or your parental unit status, and others. Too many important caveats for me to take this study with lots of confidence. You be the judge.