Using LAG Function will solve your problem.

谢谢，能不能说详细些，刚刚接触sas很多东西都不懂。

lag （）你可以看SAS字典，提取上一观测值为你所用。另外dif（）或许也能帮到你

dif()/lag(); 应该就是你想要的了

是不是这样
data test;
input Stkcd  $ date  $10.  value;
year = substr(date,1,4);
datalines;
002047 2005-06-30 6.46E+08
002047 2004-12-31 1.29E+09
002047 2003-12-31 8.96E+08
002047 2002-12-31 8.85E+08
002048 2004-12-31 2.65E+08
002048 2003-12-31 2.33E+08
002048 2002-12-31 1.5E+08
002049 2004-12-31 1.39E+08
002049 2003-12-31 1.2E+08
002049 2002-12-31 98444650
002050 2005-06-30 3.02E+08
002050 2004-12-31 3.64E+08
002050 2003-12-31 2.13E+08
002050 2002-12-31 1.34E+08
600000 2005-09-30 1.57E+10
600000 2004-12-31 1.68E+10
600000 2003-12-31 1.2E+10
600000 2002-12-31 8.16E+09
600001 2005-09-30 1.57E+10
600001 2004-12-31 1.95E+10
600001 2003-12-31 1.27E+10
600001 2002-12-31 7.88E+09
600003 2006-09-30 5.31E+08
600003 2005-12-31 6.26E+08
600003 2004-12-31 5.77E+08
600003 2003-12-31 5.58E+08
600004 2004-12-31 1.54E+09
600004 2003-12-31 1.06E+09
600004 2002-12-31 9.4E+08
600005 2005-06-30 2.15E+10
600005 2004-12-31 2.41E+10
600005 2003-12-31 6.81E+09
600005 2002-12-31 6.76E+09
600006 2006-06-30 4.89E+09
600006 2005-12-31 8.8E+09
600006 2004-12-31 6.1E+09
600006 2003-12-31 5.85E+09
600007 2005-09-30 5.75E+08
600007 2004-12-31 7.11E+08
600007 2003-12-31 6.47E+08
600007 2002-12-31 6.52E+08
600008 2005-09-30 3.45E+08
600008 2004-12-31 3.13E+08
600008 2003-12-31 2.34E+08
600008 2002-12-31 2.03E+08
600009 2005-09-30 1.95E+09
600009 2004-12-31 2.35E+09
600009 2003-12-31 1.78E+09
600009 2002-12-31 1.7E+09
600010 2005-09-30 1.45E+10
600010 2004-12-31 1.62E+10
600010 2003-12-31 1.07E+10
600010 2002-12-31 6.4E+09
600011 2005-09-30 2.91E+10
600011 2004-12-31 3.03E+10
600011 2003-12-31 2.35E+10
600011 2002-12-31 1.87E+10
600012 2005-09-30 1.14E+09
600012 2004-12-31 1.24E+09
600012 2003-12-31 8.97E+08
600012 2002-12-31 7.52E+08
;

proc sort data=test out=testSort;
   by stkcd year;
run;

data test_1;
    set testsort;
    if first.stkcd then year_rate = 0;
        else year_rate = (value - lag(value))/lag(value);
        by stkcd;
run;

proc sql;
    select stkcd, sum(year_rate)/(count(stkcd)-1) as avgl_rate
        from test_1
        group by stkcd;
quit;