[Morad Bali]

Wow I have check the .dta file too fast.

All is already done.

So please, can you just confirm me that the "." aren't a problem for the calculs ? I don't want them to be counted as "0".

Thank you very much for your time !!!!! This forum is a really great help.

[Clyde Schechter]

No, the "." are how Stata displays missing values. They aren't counted as 0; they aren't counted as anything at all. They are excluded from calculations altogether (in most situations). Read -help missing values- and the corresponding section of the [U] manual. This is very basic knowledge that you need in order to use Stata effectively.

To sort dates from earliest to latest, the command is -sort date-. To sort from latest to earliest, it would be -gsort -date-.

[Morad Bali]

Thank you Clyde !! =)