Good evening,
I would like to ask a question about my dataset:
This is how my data look like

Code:
dataex czone yr d_tradeusch_pw d_tradeotch_pw_lag
* Example generated by -dataex-. To install: ssc install dataex
clear
input double czone int yr double(d_tradeusch_pw d_tradeotch_pw_lag)
 100 2000  6.619860996926994  8.968400138934589
 100 1990  5.293786338666029 2.2788275965014972
 200 2000  10.26074591037884  4.481700814783771
 200 1990  3.030479166438892 2.7977347122308376
 301 1990  2.062596351676532  .7209086374351001
 301 2000  6.197857644865427  4.071751744428919
 302 1990 1.0783084976265715 1.4521378654168031
 302 2000 3.1115462273755705   2.90649870012464
 401 2000   2.98923875997982 2.5337993950305053
 401 1990 1.0160847787977956 1.3338325999976401
 402 1990 3.2766714138018473 1.8541934580821757
 402 2000  9.941081029296056  3.967141793376032
 500 2000  4.671787603892876 3.9520253431684047
 500 1990 2.0505001447139284 1.1078138252530074
 601 2000  6.879608543270431  5.081775879995593
 601 1990 2.5728526981305695 3.7003944704500213
 602 1990 4.3025831157713785  4.177617762298919
As you can see I have a panel data on two time periods, which are actually differential changes (1990-2000, 2000-2007), and I am looking for a way to reshape the dataset into a long interval 1990-2007 by czone. Could somebody give me some advices? I can't think of a rapid solution.

I am new to the forum so I hope that I followed the procedure in the correct way

Kind Regards
Guido Ardizzone