I'll answer your question a little differently. The last jazz artist to have a #1 record on the pop charts was Louis Armstrong. Though the song, Hello Dolly, wasn't jazz. The year was something around 1964, if my memory serves me correctly.
Chuck Mangione never achieved #1, but he made a pretty big hit out of his "Feels So Good" album (around 1977 or 78?). I guess the bottom line is that it's been a very long time since anyone associated with jazz has made a move on the pop charts.