01       First grade
02       Second grade
03       Third grade
04       Fourth grade
05       Fifth grade
06       Sixth grade
07       Seventh grade
08       Eighth grade
09       Ninth grade
0K       Kindergarten
10       Tenth grade
11       Eleventh grade
12       Twelfth grade
20       Non-Degree or Temporary Undergraduate in Postsecondary school
21       Postsecondary First Year Student
22       Postsecondary Sophomore
23       Postsecondary Junior
24       Postsecondary Senior
25       Postsecondary Post-Baccalaureate Student
26       Postsecondary Non-Degree Graduate Student
27       Postsecondary Professional Student
28       Postsecondary Master's Degree Student
29       Postsecondary Doctoral Student
30       Postdoctoral Student
31       Postsecondary Bachelor Preliminary Year
32       Postsecondary Fifth Year Student
33       Postsecondary Masters Qualifying Year
AD       Adult
AS       Associate Degree
BD       Baccalaureate (Bachelor's) Degree
C2       Medical Test (Trial)
DD       Doctoral Degree
EL       Elementary School
EM       Employment
HG       High School Graduate or Equivalent
HS       Attended high school, but did not graduate.
IF       Infant (0 to age 2)
IN       Intramural
MD       Master's Degree
MS       Middle or Junior High School
NO       None
P0       Pre-Kindergarten Level 0
P1       Pre-Kindergarten Level 1
P2       Pre-Kindergarten Level 2
P3       Pre-Kindergarten Level 3
P4       Pre-Kindergarten Level 4
P5       Pre-Kindergarten Level 5
PC       Postsecondary Certificate or Diploma
PD       Professional Degree or Certification
PF       Professional
PK       Pre-Kindergarten
PS       Some Postsecondary (e.g., college)
SS       Secondary School
UN       Ungraded
VR       Varsity
VS       Vocational School