Dear All, Suppose that the data set is
Code:
* Example generated by -dataex-. To install: ssc install dataex
clear
input str6 Stkcd str10 riqi byte(Position Changtyp Edca Dimreas Dimage) double Years byte Entele
"000001" "2002-04-30" 1 1 4  . 56  3.17 .
"000001" "2003-09-04" 1 2 4  .  .     . 1
"000001" "2003-10-16" 2 1 4  3 52     6 .
"000001" "2003-10-16" 2 2 4  .  .     . 1
"000001" "2004-12-14" 1 1 4  3 53     1 .
"000001" "2004-12-14" 1 2 5  .  .     . 2
"000001" "2004-12-14" 2 1 4  3 42     1 .
"000001" "2004-12-14" 2 2 4  .  .     . 2
"000001" "2005-05-16" 1 1 5  5 62    .5 .
"000001" "2005-05-16" 1 2 3  .  .     . 1
"000001" "2005-06-17" 1 2 3  .  .     . 1
"000001" "2005-06-17" 1 1 3 12 62    .1 .
"000002" "2006-02-11" 2 1 4  5 53   1.1 .
"000002" "2007-02-07" 2 2 2  .  .     . 1
"000002" "2010-06-29" 1 1 3  5 68     5 .
"000002" "2010-06-29" 1 2 2  .  .     . 1
"000002" "2010-06-29" 2 1 2  1 62  3.33 .
"000002" "2010-06-29" 2 2 .  .  .     . 1
"000002" "2010-10-13" 2 1 . 12 54   .25 .
"000002" "2010-10-13" 2 2 .  .  .     . 1
"000002" "2012-11-21" 2 1 .  8 56  2.08 .
"000002" "2012-11-21" 2 2 5  .  .     . 2
"000002" "2012-11-21" 1 1 .  8 64  2.42 .
"000002" "2012-11-21" 1 2 2  .  .     . 2
"000003" "2016-10-20" 2 1 5  5 59  3.92 .
"000003" "2016-10-20" 2 2 4  .  .     . 1
"000003" "2016-11-06" 1 1 2  3 63  3.96 .
"000003" "2016-11-07" 1 2 4  .  .     . 1
"000003" "2016-12-10" 1 1 4 12 45   .09 .
"000003" "2016-12-10" 1 2 5  .  .     . 2
"000003" "2016-12-10" 2 1 4 12 54   .14 .
"000003" "2016-12-10" 2 2 4  .  .     . 1
"000003" "1999-02-08" 2 1 .  9 48     8 .
"000003" "1999-02-08" 2 2 3  .  .     . 1
"000004" "2001-02-15" 2 1 3  7 49     2 .
"000004" "2001-02-15" 2 2 4  .  .     . 1
"000004" "2002-06-12" 1 2 3  .  .     . 1
"000004" "2017-06-29" 1 1 3  3 66 15.06 .
"000004" "2017-06-30" 1 2 4  .  .     . 1
end
For each Stkcd and each year, I'd like to keep the last observation(s) occurred in each year.

Note that, if there are more than one observation with the same last date, keep them all. Thanks.