Hi,

I managed to gather data for inflation from the IMF but its measure is (Prices, Consumer Price Index, All Items, Corresponding period, previous year, percent).

However, I'm only interested to get the inflation rate for quarter given that my data is quarterly data. To my understanding, I would think that the variable I gathered is in first difference.

This is my variable information
Code:
* Example generated by -dataex-. To install: ssc install dataex
clear
input double inf
 7.74278215223094
 10.2464332036316
  12.291933418694
 13.1147540983606
 14.7381242387332
               14
 13.5689851767389
 12.3745819397994
 11.8895966029724
 11.0423116615067
 10.8433734939759
 11.6071428571428
 9.77229601518024
  9.1078066914498
 7.78985507246374
 7.28888888888891
 6.30942091616251
 6.47359454855195
 6.13445378151261
 5.96520298260146
 5.69105691056911
 5.75999999999999
 5.77988915281077
 5.62939796716187
 5.76923076923076
 6.05143721633889
 8.00898203592812
 8.80829015544041
 9.96363636363637
 9.70042796005709
 7.90020790020794
 7.41496598639454
 7.07671957671957
 7.02210663198959
 6.61528580603723
 6.01646611779607
 4.69425571340333
 4.67800729040098
 4.51807228915663
 4.30107526881723
 4.36578171091446
 3.83052814857803
 3.80403458213255
   4.524627720504
 3.90050876201245
 3.80100614868644
 3.49805663520268
 2.57534246575342
 2.33949945593033
  2.4232633279483
 2.30686695278971
 2.24358974358973
 2.60499734183944
 2.41850683491062
 2.14997378080752
 1.98537095088822
  1.2435233160622
 .975359342915802
 1.54004106776183
 1.74180327868853
 2.66120777891503
 2.69445856634468
  2.3255813953488
 2.16515609264855
 .897308075772663
 .990099009900991
 1.38339920948619
 1.77427304090683
 3.06324110671939
 2.69607843137256
 2.29044834307992
 2.22760290556901
 2.15723873441995
  2.2434367541766
 2.28680323963794
 2.32117479867363
 2.25246363209761
 2.47432306255837
 2.04937121564973
 2.68518518518515
 2.89123451124368
 2.91571753986331
 3.42309447740759
 3.11091073038775
 3.52363960749332
 3.93979637007527
  2.5595763459841
  2.0113686051596
  1.0340370529944
 .468483816013621
 1.41996557659209
 2.22888984140592
 4.60554371002131
 2.24671470962272
 1.90920661858297
 1.21593291404613
-1.42682429677945
 .829187396351576
 1.20732722731057
 1.24275062137531
end
1. Is there a code to get the inflation rate for the quarter for the information I've got?
2. Given that this is the first difference of the change in inflation, how do I code such that Stata treats this as a first difference operator? (i.e D.inf)

Thank you.