You Are Involved in the Big Brother/Big Sister Program

You are involved in the Big Brother/Big Sister program.Your "little" just told you that he is considering dropping out of high school.You are horrified that he would consider doing this.What is one of the reasons that this is going to be a huge problem for him? The average salary for high school dropouts has ____.

A) only increased by 12% over the last half-century
B) only increased by 5% over the last half-century
C) decreased by 28% over the last half-century
D) decreased by 42% over the last half-century