Hi Everyone,

I am looking to create a yearly count and cumulative sum variable based on a string identifier, CUSIP. Following is the example generated by dataex:

input long patent_num int cites str8 CUSIP str4 year
3915372 16 "00003210" "1975"
3946915 37 "00003210" "1976"
3935990 20 "00003210" "1976"
3935991 17 "00003210" "1976"
4039119 12 "00003210" "1977"
4039121 19 "00003210" "1977"
5839505 34 "00036020" "1998"
5826641 24 "00036020" "1998"
5738167 10 "00036020" "1998"

So for example, for the CUSIP code 00036020, the count for patent would be 3 and the cumulative cite would be 68 (34+24+10). What should be the appropiate code to generate such count variables for inputs like patent, cites etc?

Thanks in advance!