After decades, i expect 75%. Know what it takes to make a good shot and do not push the button if all is not correct. Spray and pray may work with a machine gun, rearely with photography.
Are you serious? Such a percentage is about 100x too optimistic for most forms of RF photography (e.g. documentary/street) at the top end of the quality scale. Sounds like you are playing it waaaaay too safe. Do you no longer experiment or try new things?
When working various styles under certain circumstances, one needs to work in a very intuitive, fluid manner and that means not getting the right shot a lot of the time, but it does mean that you have to keep moving, shooting, engaging, shifting, shooting, re-engaging etc. Its not a question of pray and spray necessarily but accepting that there are so many things to bring together in space and time and your ability to monitor them all, in detail and perfectly, is limited. I know that if i waited for everything to be clearly perfect in the frame I would miss far more than I would gain by being somewhat more relaxed and instinctive. I get a fair few shots by anticipating or simply going with the flow. And this does demand skill of the photographer!
Your exceptionally methodological approach could be considered equally unconducive to the best results as 'spray and pray' and I think we would struggle to find even a BTZS LF worker that could come even close to this sort of success rate. If, however, a person is using a RF to take very safe landscape shots or static objects, such as steam locomotives, the success rate is going to be much higher for the intended goal, but that does not mean the shot is 'any good' only that you produced a correctly exposed shot with the composition as intended and with very easy goals. If I counted all my keepers as 'well exposed and looking sensible' my percentage would be a lot higher, but I am not sure this is what a keeper is to most people. I think they are talking about something you would put in a portfolio that you would show, or perhaps put in front of a critical eye, or consider a shot you feel represents your high standards and best level of achievement.