Great song. Ironically, his signature tune was not a huge hit as a single when it was originally released.
I always had a lost of mistrust for Billboard's HOT 100 chart. Over the years, they have changed their methodologies of determining what was a hit so many times that you simply cannot compare one era to aother.
Back in the early 1970s, airplay on just a few AM Top 40 stations and record sales in a relatively small sampling of retail record stores determined where a record sat on the charts. Also, in order to chart on the HOT 100, the song had to be an officially released single (not just an album track).
So it was very easily manipulated. If you could get a handful of key stations to play the new Barry Manilow song and send a pallet of the 45 singles to each of the key record stores at a discount (to the stores), you could get that song up in the Top 10 in no time at all.
Nowadays, chart placement is determined mostly by how many times a song is streamed on the various platforms like Spotify and Pandora. It's overall a better way of doing things but the charts look a lot stranger these days, as a new album release by an established superstar can have every single album track placed in the HOT 100 all at once.
About a year ago, country star Morrgan Wallen released a 36-track album and every single cut made the HOT 100 that week. It was bandied about that Morgan smashed The Beatles record of having a bunch of songs on the charts back in 1964.
Not quite the same thing however. Not even close.