st: calculating percentage changes in an unbalanced panel data set

[Tzaloupas Dimitrov <tzaloupas1232@yahoo.gr>]

Dear all,

I have some time series observations (inflation) for a set of countries

The panel data set is unbalanced, that is,

egen id = group(country), label
tsset id time
       panel variable:  id (unbalanced)
        time variable:  time, 01oct2008 to 01nov2011, but with gaps
                delta:  1 day

within each country I want to find the percentage change of inflation.

I tried 

bysort country time : gen p2=(inf[2]-inf[1]/inf[1])*100

but I get this message 
(500 missing values generated)

 Am I doing something wrong?



I use Stata 11

Any help/code is greatly appreciated

Thanks in advance            

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