Hello,

I have some troubles in counting the firm number in panel data. I have 3741 fiscal year observations during 1994-2006. And I want to count how many firms are there in my sample.

I used the command below:
bysort fyear gvkey
count gvkey

"fyear" is the fiscal year and "gvkey" is the company ID.

But there always shows an error as ": required r(100);" in Stata.

So could you please tell me what I am doing wrong? Thank you very much!