Bernie Parents Flyers sv% was ~0.917.
The hockey summary project, flyers history and a few guys doing blogs estimated historical sv% and 3 different guys came to the .917 estimate.
Full stats as per Flyers history:
1967-68: 38gp, 0.926sv%
1968-69: 58gp, 0.923sv%
1969-70: 62gp, 0.920sv%
1970-71: 30gp, 0.912sv%
1973-74: 73gp, 0.933sv%
1974-75: 68gp, 0.919sv%
1975-76: 11gp, 0.908sv%
1976-77: 61gp, 0.897sv%
1977-78: 49gp, 0.912sv%
1978-79: 36gp, 0.893sv%
Overall: 486gp, 0.917sv%
Playoffs:
1968: 5gp, 0.963sv%
1969: 3gp, 0.872sv%
1974: 17gp, 0.933sv%
1975: 15gp, 0.922sv%
1976: 8gp, 0.892sv%
1977: 3gp, 0.814sv%
1978: 12gp, 0.891sv%
Also a pretty interesting read, though the methodology is not great:
http://brodeurisafraud.blogspot.co.uk/2009/04/estimating-1970s-save-percentages.html
Showing just how bloody good Parent was... sv% was averaging ~.900 when he played for the Flyers, yet overall he put up ~.917.