On: 2019 Stack Overflow Developer Survey Results

[trymas]

Multi answer questions in the survey may explain that?

[the_arun → trymas]

I see. One way of calculating % in multiple choice is ((total No. of C likers)/ total count of answers) * 100 to get % of popularity of C.

[fxfan → the_arun]

You can just add all the percentages and divide by that number and you'll get the number you're talking about.