1. "60% of the time it's what sampled it" In response to In response to 0
a lot of less-than-a-dollar records got pumped up to insane amounts after being sampled (and being popular off that). Like Skull Snaps, especially. "Impeach The President" wasn't that popular a song until it was sampled.
the 40% when it's not, is when it's a straight jack or an "obvious" jack of a song that was popular in the first place.
Like most James Brown (I wouldn't say "Funky Drummer" counts, because it wasn't included in Greatest Hits collections for a while).