Let’s look at a recent paper by Xia, Bao, Lo, Xing, Hassan, & Li entitled Measuring Program Comprehension: A Large-Scale Field Study with Professionals and published in IEEE Transactions on Software Engineering, 44, 951-976, 2018. This paper is quite interesting in that it describes in great details how the figures are obtained. And it says that Comprehension took on average ~58%.

So much ?!