Comparing constant dollars between different years can be misleading due to inflation. For example, if a woman earned $30,000 a year in 1990, economists estimate that her daughter would have needed to earn over $53,500 to have the same real income in 2014.
A graph of average income between the day you were born and today would be much easier to understand if each year’s average income was displayed in today’s dollar value; hence the popularity of reporting constant rather than nominal dollars.
For a conversion of dollar values between years, see: http://www.westegg.com/inflation/
She is exaggerating her point by using nominal dollars in the graph.
It was not that she lent money on interest, but it was known, for instance, that she had for some time past, in partnership with old Karamazov, actually invested in the purchase of bad debts for a trifle, a tenth of their nominal value, and afterwards had made out of them ten times their value.