Hello

I would appreciate if someone can tell me the command that would reshape my data from
2012 2013 2014 2015
1
2
3
4
5
to something like
1 2012
1 2013
1 2014
1 2015
2 2012
2 2013
where the empty cells would just contain the data. As you can see, I basically want to go from the first shape to a panel data shape.
I would appreciate any input !

Regards,