* This file reads merged1 and keeps selected variables;
* It creates a sas file called merged2
*****************************************************
options compress=yes;
libname in 'D:/cm/';
libname un 'D:/enrico/imported/data';


data tmp92; set in.merged1;
if yr ^= 92 then delete;
id92 = id;
ind92 = ind;
fst92 = fst;
county92=county;
smsa92 = smsa80;
sw92=sw;
keep id92 ppn ind92 fst92 county92 smsa92 sw92;
proc sort; by ppn;
run;

data tmp82; set in.merged1;
if yr ^= 82 then delete;
id82 = id;
ind82 = ind;
fst82 = fst;
county82=county;
smsa82 = smsa80;
sw82=sw;
keep id82 ppn ind82 fst82 county82 smsa82 sw82;
proc sort; by ppn;
run;


data in.merged2; merge tmp82 tmp92; by ppn;
proc means;
run;