AK = Alaska
AL = Alabama
AR = Arkansas
AZ = Arizona
CA = California
CO = Colorado
CT = Connecticut
DC = District of Columbia
DE = Delaware
FL = Florida
GA = Georgia
HI = Hawaii
IA = Iowa
ID = Idaho
IL = Illinois
IN = Indiana
KS = Kansas
KY = Kentucky
LA = Louisiana
MA = Massachusetts
MD = Maryland
ME = Maine
MI = Michigan
MN = Minnesota
MO = Missouri
MS = Mississippi
MT = Montana
NC =North Carolina
ND = North Dakota
NE = Nebraska
NH = New Hampshire
NJ = New Jersey
NM = New Mexico
NV = Nevada
NY = New York
OH = Ohio
OK = Oklahoma
OR = Oregon
PA = Pennsylvania
PR = Puerto Rico
RI = Rhode Island
SC = South Carolina
SD = South Dakota
TN = Tennessee
TX = Texas
UT = Utah
VA = Virginia
VT = Vermont
WA = Washington
WI = Wisconsin
WV = West Virginia
WY = Wyoming
XX = Other territories or Unknown
Null/missing = not enrolled in the
month