Dear STATAlist community,

I am looking for help in creating a dummy variable for a time series. This is a sample of the data I have so far.
Game_ID score intro intro_year intro_month
1 67 1995m1 1995 1
2 . 1996m2 1996 2
3 26 1998m8 1998 8
... ... ... ... ...
Based on this information, I would like to build dummy variables that depict wether the Game (Game_ID) was introduced before a specific date. To make it easier to imagine, here is a table of how I would like to have it look like. The exact naming of the dummy variables is not of big importance, however, they should include the year and the month.
Game_ID score intro intro_year intro_month available_1995m1 available_1996m2 available_1998m8
1 67 1995m1 1995 1 1 1 1
2 . 1996m2 1996 2 0 1 1
3 26 1998m8 1998 8 0 0 1
... ... ... ... ... ... ... ...
I am very thankful for all the help I can get. The problem I have had so far was mainly about the naming of the variables. Here is what I have so far. I used the help of a "time ID".

egen time_id =group(intro_year intro_month)

order time_id
forvalues i = 1(1)183 {
gen av`i'= 1 if time_id <=`i'
replace av`i'= 0 if time_id >`i'
}

Thanks for taking the time.