Good question. I would say 98%+. And this has not always been true. My previous system which I used to refer to as my "Reference System", probably only 10 - 20 % sounded really good. I referred to it as my "Reference System" because it was so detailed and sensitive to the mastering and ambience of the recording. If anything was off I would hear it. Here is a vastly simplified version of one of the steps that took me from 10% to 98% sounding good.
I upgraded my headphone system to a 300B high end headphone amp (Woo WA5). I was shocked at the power, warmth, and musicality of the sound. I remember listening to it the first time. Thinking... wow, that sounds great, I have to go listen to my main system to get the full impact and soundstage. I turned on my main system and it sounded terrible... flat, trebly... like missing the midrange... it was sterile and analytical. It was a $70K system that sounded like schiit in comparison to my headphone system.
That was the end of my reference system. I immediately started building my next system with emphasis on sounding like "the real thing"... not hyper details and bass. I experienced a decade of season tickets to the symphony and lots of listening to individual unamplified instruments and small groups. What I built is incredibly compelling, musical and emotionally involving. Only albums that sound terrible will come across as such. All the details are there... they are just not highlighted and emphasized. The midrange is natural and fully bloomed.
So, it is critical how you build your system as to the percent of recordings will sound good.