Girsempa said: I know that some professional photographers shoot in jpg most of the time. Why they do that?

Depands on what their shooting...most if not all paps shoot jpg purely so they then wi-fi  them straight to the desk quicker, remember, time is a premium to them.

Ok, Raw files take up more mb's than  jpgs do.  I for one cannot sacrifice space over 16 bit quality!
Raw v JPG: I shoot/shot  Raw for many yrs. Raw can convert to 16bit TIFFs whereas JPG are only 8 bit regarless on what format one saves them too.
Can pull back the highlights, the exposure, white balance...kinda stuck in jpg (unless one knows how to work the cam:-)