The likelihood of ending up in the same economic position as your parents has since about 1980. depended upon your economic class stayed about the same been rising been falling

Been rising.

Explanation:

The likelihood of ending up in the same economic position as your parents has been rising since about 1980. In open systems, mobility is a key aspect, because according to your merits and hard work you can achieve a better position as you thrive for a better living. But since 1980, studies show that mobility has decreased and that it has become more difficult to raise many steps in economic positions.

answer; proximity;