IIRC the standard for serfs was 2-3 days of labor per week (in some cases during harvest even up to 5), for a 6 day workweek. Add various random fees and rents and that's way more than 50-60%.

Of course everything improved massively after the plague. So it depends on which part of the middle ages we're talking about.

It’s 15% for the commoners (<$1M) and I’d believe that in feudal times.