"Grover Washington Jr." was certainly popular in the 70's. That's when I was traveling a lot between St. Louis and Atlanta, and Grover Washington was very popular in both places. He was one of the most consistent musicians when it came to good sounding music; that continued up until his death in 1999.
In 1971, he came out with an album titled "Inner City Blues", and there was not one bad cut on it; as a matter of fact, I have to present 3 cuts on that album: Inner City Blues; Mercy Mercy Me, and Ain't No Sunshine.
https://www.youtube.com/watch?v=VUxHao8aZPI&list=PLutzgs53WVha-XVfWBt4zEqpnhCfoiMl5
https://www.youtube.com/watch?v=0CXWsVg3ZC4
https://www.youtube.com/watch?v=jKfiyY9UcpI
Those three cuts were from the same album. I bought that album when it came out, and it is well worn.
This is what "Wiki" says about Grovers style; Fusion, Jazz-Funk, Smooth Jazz; I'm not quite sure I know what all that means, but when Grover does it, I like it.
One last time for Grover;
https://www.youtube.com/watch?v=NaeEEqA3pPs
Enjoy the music.