Hello!

Code:
* Example generated by -dataex-. For more info, type help dataex
clear
input float(fundnr month year mf_m_cf)
1  7 2011          .
1  8 2011   81.92355
1  9 2011   476.8079
1 10 2011   21.52062
1 11 2011   2.582487
1 12 2011   6.664676
1  1 2012   8.380138
1  2 2012   1.357534
1  3 2012   8.550103
1  4 2012  -2.678535
1  5 2012   5.655555
1  6 2012   2.504373
1  7 2012 -.12116786
1  8 2012  4.5901546
1  9 2012    .600794
1 10 2012  .29563415
1 11 2012   3.328934
1 12 2012  1.4961462
1  1 2013  .54998076
1  2 2013   4.551462
1  3 2013   .6748788
1  4 2013   .4444814
1  5 2013 -.01265101
1  6 2013   .6499855
1  7 2013  1.6610664
1  8 2013   2.949057
1  9 2013   3.399674
1 10 2013   9.943465
1 11 2013   .2990036
1 12 2013  -.3797645
1  1 2014  -1.064931
1  2 2014  .24728173
1  3 2014   1.374272
1  4 2014  -3.390731
1  5 2014    .359465
1  6 2014  -.4076815
1  7 2014 -1.1045641
1  8 2014   -.697988
1  9 2014  -.8082402
1 10 2014 -.13452792
1 11 2014  1.3073466
1 12 2014 -2.0818634
1  1 2015  -4.356202
1  2 2015  2.8146536
1  3 2015  -.6765027
1  4 2015  -83.74078
2  8 2011          .
2  9 2011  4.5467353
2 10 2011   6.979911
2 11 2011  8.1631975
2 12 2011   .6553888
2  1 2012  1.0961826
2  2 2012  -2.891215
2  3 2012  1.5067998
2  4 2012   24.91592
2  5 2012  -.2980085
2  6 2012  -.4910712
2  7 2012 -.22777045
2  8 2012  -.9225484
2  9 2012  -.8890392
2 10 2012 -1.3467927
2 11 2012  -3.202692
2 12 2012 -2.0998995
2  1 2013   5.050189
2  2 2013   3.924864
2  3 2013  -1.263452
2  4 2013  -.5413366
2  5 2013  1.5253117
2  6 2013  -.9724789
2  7 2013 -3.5416684
2  8 2013  -.2780949
2  9 2013  -.4938647
2 10 2013   4.586828
2 11 2013  .23677163
2 12 2013  -1.385884
2  1 2014  .13616227
2  2 2014  -2.955069
2  3 2014 -1.5510585
2  4 2014 -1.4003643
2  5 2014  .27552602
2  6 2014  -.7300715
2  7 2014  -.8981757
2  8 2014 -1.3882908
2  9 2014 -1.1608492
2 10 2014   1.369086
2 11 2014   .7596431
2 12 2014 -4.2625575
2  1 2015  1.0341657
2  2 2015  -.0750414
2  3 2015 -.20450144
2  4 2015  -2.822578
2  5 2015  -.9178555
2  6 2015 -1.2965387
2  7 2015  -.3353655
2  8 2015   2.649211
2  9 2015 -.32353655
2 10 2015  -.0687631
2 11 2015  -.9628157
2 12 2015 -1.1600745
2  1 2016  -.8803672
end
For clarification: mf_m_cf stands for 'Monthly Flow in % following Sirri/Tufano' and I am trying to get the yearly flow in %. I dont think I can just add the monthly flow in % for each fundnr in each year, is there perhaps a Stata function for this?