Down to the lines of code written? Your product may get millions in revenue, but you wrote a single module out of hundreds, how much % do you take credit for?

Down to the lines of code written? Your product may get millions in revenue, but you wrote a single module out of hundreds, how much % do you take credit for? Also it sounds like a toxic culture if you have to constantly try to tie your day-to-day work directly to how it impacts new revenue and profits or else your work is considered worthless.