a factor with levels Alabama
,
Alaska
, Arizona
, Arkansas
, California
,
Colorado
, Connecticut
, DC
, Delaware
, Florida
,
Georgia
, Hawaii
, Idaho
, Illinois
, Indiana
,
Iowa
, Kansas
, Kentucky
, Louisiana
, Maine
,
Maryland
, Massachusetts
, Michigan
, Minnesota
,
Mississippi
, Missour
, Montana
, Nebraska
,
Nevada
, New Hampshire
, New Jersey
, New Mexico
,
New York
, North Carolina
, North Dakota
, Ohio
,
Oklahoma
, Oregon
, Pennsylvania
, Rhode Island
,
South Carolina
, South Dakota
, Tennessee
, Texas
,
Utah
, Vermont
, Virginia
, Washington
, West
Virginia
, Wisconsin
, and Wyoming