This Congress, the 116th, will have presided over the fewest new laws of any Congress in a generation. With legislative activity nearly concluded for the year, and therefore for this Congressional session, just 226 bills, or 1.36% of the 16,557 bills introduced, eventually became enacted law.

That 1.36% and 226 bills total is the lowest percentage and lowest total number of introduced bills to become law since the 93rd Congress (1974, the oldest data set available on GovTrack). However, GovTrack notes that the total number of words in all bills passed has remained consistent, suggesting that there are less bills passed, but they tend to be much larger (longer) now than, say, 50 years ago.

As of this writing the President has not signed H.R. 133 (aka Coronavirus Stimulus Act) into law although he is expected to do so soon. That would bring the total bills passed to 227, still the fewest in a generation.

Since the 93rd Congress (January 1973 - December 1974), the most prolific Congressional sessions were:

95th [Jan 4, 1977 -Oct 15, 1978] with 804 bills becoming law, 3.6% of the 22,313 introduced.

100th [Jan 6, 1987 -Oct 22, 1988] with 761 bills becoming law, 6.7% of just 11,278 introduced.

101st [Jan 3, 1989 -Oct 28, 1990] with 665 bills becoming law, 5.6 % of 11, 787 bills introduced.

Source:
https://www.govtrack.us/congress/bills/statistics