It's currently hard to tell because of the renewal exemption (https://letsencrypt.org/docs/rate-limits/):
Renewals are treated specially: they don’t count against your Certificates per Registered Domain limit, but they are subject to a Duplicate Certificate limit of 5 per week. Note: renewals used to count against your Certificate per Registered Domain limit until March 2019, but they don’t anymore.
Unless you perfectly know the historical lineage of a certificate (i.e. by looking in the Let's Encrypt database which has an optimized index for it), finding the true state of the rate limit state takes a lot of expensive queries against a traditional log aggregator, probably to the point where it's infeasible to do casually. Especially if you have 300+ certificates being renewed per week.
