How were the numbers uner 'Ratio', 'Train', and 'Val' calculated in objectInfo150.txt?

[YellowPig-zp]

I am trying to understand where 'Ratio', 'Train', and 'Val' come from in the objectInfo150.txt file.

Presumably the 'Ratio' is the pixel ratio of each category presented over all the images. I tried to reproduce the number for the 'wall' category by 1) counting the number of pixels labelled with '1' for each image, divided by the total number of pixels in the image, then averaged over total number of images under the training/validation set separately/altogether; 2) similar to 1) but averaged over the sum of total number of pixels in all images. Neither approach successfully reproduce the number(around 0.1 off 0.1576)

I guess the numbers under 'Train' and 'Val' are the instance counts for each category? For this I simply count if the category 'wall' is present in every image under the training and validation sets. Since 'wall' is a stuff I guess it is sufficient to just check existence. But the numbers also don't match (11588 vs. 11664, 1167 vs. 1172)

I want to ask where my understanding goes wrong? Thanks a lot!