Slade's seasonal classic "Merry Xmas Everybody" has been a perennial favorite in England since its release in December 1973. Believe it or not, decades later, the song stood to make an estimated £800,000 in royalties as recently as 2013. That's a little over $1.3 million.

In fact, "Merry Xmas Everybody" is the top earning Christmas song when it comes to royalties when you take into account radio airplay, use on television, jukeboxes, compilation albums and record sales. Upon its initial release, the rollicking holiday stomper entered the U.K. charts at No. 1, but that was far from the end of the story. The record was re-released in 1980 and every Christmas season afterwards through the '90s, and again in the mid-'00s. Each and every time it has been put back out, "Merry Xmas Everybody" has made the charts -- reaching No. 21 in in 2014, for instance.

In a 2009 interview on the British television show, the Wright Stuff, Slade guitarist Noddy Holder, who co-wrote the song with bassist Jim Lea, explained its origin. "It took a couple or three days really. No one at that time was doing it, so we came up with a Christmas song. It was 1973, it was the middle of a recession at that time. It was a really bad time, and this was an optimistic record, (saying) 'Look to the future it's only just begun!'"

See the Top 100 Albums of the '70s