Add 18 to 2016 and you will get the approximate year. This is assuming you do your school years without repeating a grade or that you do 4 years in high school. Some people take 5-6 years to graduate high school.
Assuming that Suzanne Collins started high school when she was 14 (1976), and again assuming that she graduated when she was 18. she would have graduated in 1980. She graduated from Alabama school of fine arts in 1980