Most 5 set matches at a Grand Slam tournament in the Open Era?

Question

What is the record for the most number of five-set matches at a Grand Slam tournament in the Open Era?
Where does the 2019 US Open (27 five-set matches) rank in the all-time list?

Answer 1

According to the data provided by Jeff Sackmann, these are the Grand Slams with the most 5 setters since 1969:

Year	Grand Slam	5 set matches
1969	Wimbledon	34
1983	US Open	34
2004	US Open	34
1992	Roland Garros	33
1994	Wimbledon	33
2001	Roland Garros	33
2010	Wimbledon	33
2012	Wimbledon	32
1976	Roland Garros	31
1998	Australian Open	31
2001	Wimbledon	31
2015	Wimbledon	31

2019's US Open would rank only 36th in that list.