Hi Community,

for a paper at university i need to calculate the annualized standard deviation of daily returns. Here is an example of my dataset.
For every company and every year i need to have one standard deviation in the end. I used this code but i am not sure if this i correct as i get one value per year but it is written in the cell for every day of the respective year.
Code:
bysort company_code year: egen sd = sd(r_s_)
Here is an example of my dataset.

Code:
* Example generated by -dataex-. To install: ssc install dataex
clear
input int(date company_code) float r_s_ int year float sd
15582 1   .002399484 2002 .01745268
15446 1     .0232559 2002 .01745268
15488 1  -.009186814 2002 .01745268
15349 1  -.003483082 2002 .01745268
15564 1  -.004130152 2002 .01745268
15629 1  -.015606005 2002 .01745268
15369 1  -.017244903 2002 .01745268
15546 1   .001918968 2002 .01745268
15540 1   -.06892748 2002 .01745268
15449 1   .009737544 2002 .01745268
15348 1  -.005637663 2002 .01745268
15565 1  -.013059427 2002 .01745268
15558 1    .03874377 2002 .01745268
15621 1    .02572878 2002 .01745268
15370 1    .01116412 2002 .01745268
15533 1  -.004375924 2002 .01745268
15631 1  .0018404057 2002 .01745268
15411 1   .006621597 2002 .01745268
15662 1   -.01556447 2002 .01745268
15392 1  -.009436125 2002 .01745268
15587 1   .005150879 2002 .01745268
15400 1   .020069323 2002 .01745268
15594 1  -.010358914 2002 .01745268
15431 1  .0021702978 2002 .01745268
15455 1   .011486853 2002 .01745268
15468 1   .015092998 2002 .01745268
15433 1  -.018251505 2002 .01745268
15652 1  -.002409909 2002 .01745268
15537 1   -.02547316 2002 .01745268
15593 1   .009069891 2002 .01745268
15614 1    .05579595 2002 .01745268
15384 1   .014257977 2002 .01745268
15376 1  -.007514463 2002 .01745268
15693 1 -.0046421625 2002 .01745268
15368 1  -.006221036 2002 .01745268
15398 1  -.002517924 2002 .01745268
15459 1  -.014249854 2002 .01745268
15393 1   .025527457 2002 .01745268
15480 1  -.014173967 2002 .01745268
15544 1    .02500148 2002 .01745268
15379 1   .015405613 2002 .01745268
15553 1   -.02984902 2002 .01745268
15526 1    .02945707 2002 .01745268
15497 1  -.017487248 2002 .01745268
15679 1  -.016542573 2002 .01745268
15669 1  -.008354846 2002 .01745268
15648 1  .0019549874 2002 .01745268
15453 1  -.005857047 2002 .01745268
15586 1   -.04016614 2002 .01745268
15439 1   .010381272 2002 .01745268
15424 1  -.005940103 2002 .01745268
15622 1   -.01282654 2002 .01745268
15490 1  .0007979155 2002 .01745268
15571 1    .02125892 2002 .01745268
15651 1  -.014594428 2002 .01745268
15357 1   .010093715 2002 .01745268
15552 1  .0027046995 2002 .01745268
15664 1   .010177162 2002 .01745268
15454 1     .0097719 2002 .01745268
15383 1   .001401126 2002 .01745268
15489 1  -.014136853 2002 .01745268
15670 1  -.025590213 2002 .01745268
15692 1  -.005281798 2002 .01745268
15438 1    .01384445 2002 .01745268
15377 1   .009253282 2002 .01745268
15684 1   .008428827 2002 .01745268
15421 1   -.01628147 2002 .01745268
15483 1   .007422936 2002 .01745268
15701 1   -.01545622 2002 .01745268
15502 1  -.004135068 2002 .01745268
15656 1    .01140944 2002 .01745268
15511 1  -.007386164 2002 .01745268
15386 1  -.011878805 2002 .01745268
15658 1   .010208822 2002 .01745268
15435 1   .066193506 2002 .01745268
15375 1   -.03385313 2002 .01745268
15432 1  -.002347395 2002 .01745268
15607 1   -.03781525 2002 .01745268
15515 1  .0009676528 2002 .01745268
15403 1    .02210995 2002 .01745268
15445 1   -.00549482 2002 .01745268
15575 1  -.007491405 2002 .01745268
15505 1  .0019871185 2002 .01745268
15538 1   .013368674 2002 .01745268
15524 1   .002618329 2002 .01745268
15343 1 -.0033331455 2002 .01745268
15608 1  .0015075208 2002 .01745268
15685 1  -.003127726 2002 .01745268
15413 1   .009076586 2002 .01745268
15475 1  -.003779376 2002 .01745268
15418 1 -.0041044606 2002 .01745268
15666 1  -.009589176 2002 .01745268
15501 1   .012456857 2002 .01745268
15613 1  -.023192476 2002 .01745268
15477 1   .005089684 2002 .01745268
15397 1  -.009599154 2002 .01745268
15466 1   -.02213284 2002 .01745268
15595 1  -.012754117 2002 .01745268
15680 1  .0015870344 2002 .01745268
15414 1   .006694098 2002 .01745268
end
format %tdnn/dd/CCYY date
I would appreciate some help

Best Wishes, Patrick