Highest year of school respondent completed
0 = No formal schooling
1 = 1st grade
2 = 2nd grade
3 = 3rd grade
4 = 4th grade
5 = 5th grade
6 = 6th grade
7 = 7th grade
8 = 8th grade
9 = 9th grade
10 = 10th grade
11 = 11th grade
12 = 12th grade
13 = 1 year of college
14 = 2 years
15 = 3 years
16 = 4 years
17 = 5 years
18 = 6 years
19 = 7 years
20 = 8 years