I am trying to generate a new variable which consecutively categorises an existing category. I am not sure how to explain this, except by an example:

Code:
* Example generated by -dataex-. To install: ssc install dataex
clear
input float(var1 var2)
2 1
2 1
2 1
2 1
2 1
0 2
0 2
0 2
2 3
2 3
0 4
0 4
0 4
2 5
2 5
0 6
end
I have var1, and I want to generate var2. Because I am not sure how to word or explain my problem, I am not quite sure where to look for a solution. I may not require the complete solution, but if I am pointed in the right direction (or command / function) I am sure I can figure it out. (once I find the solution, I will post it for closure).

My question therefore is which command or function will allow me to generate var2 in the example above?

Thank you so much.