So, this chart, indicating that the USA has cruddy economic mobility:
Why choose fathers and sons? What does this chart look like for mothers and daughters, or household income (father and mother) and the average income of their children? A child's economic status is not solely a product of his/her father's salary, and likewise your adult status may not be a function solely of your own income (perhaps poor people are more likely in some places to marry out of their socioeconomic class. etc.).