The data set STATEPOP contains information from the 1980 and 1990 U.S. Census on the population in metropolitan and nonmetropolitan areas. The 50 states and District of Columbia are divided into four geographic regions. The data are organized by state within each region. The metropolitan and nonmetropolitan population counts are stored in one observation for both census years. A DATA step creates this data set. 
data statepop;
   input State $ CityPop_80 CityPop_90 
         NonCityPop_80 NonCityPop_90 Region;
   format region 1.;
   label citypop_80=   '1980 metropolitan pop in millions'
         noncitypop_80='1980 nonmetropolitan pop in millions'
         citypop_90=   '1990 metropolitan pop in millions'
         noncitypop_90='1990 nonmetropolitan pop in million'
         region='Geographic region';
  datalines;
ME    .405    .443   .721   .785  1   
NH    .535    .659   .386   .450  1
VT    .133    .152   .378   .411  1   

   ... more lines of data ...

CA  22.907  28.799   .760   .961  4   
AK    .174    .226   .227   .324  4
HI    .763    .836   .202   .272  4
;