The 2010s has not been a good decade for Throwback Weekends, as the songs atop the Billboard Hot 100 did not shift much that year. It is also a year I was already blogging, so newcomers to the list have often already been featured here.

This week, at least, the glut of familiar songs among the top ten paid off. I had to drop all the way to #13 to find a song I haven’t written about, and it happens to be a perfect thematic fit on this Christmas Eve — ‘Little Drummer Boy’ by the a cappella group Pentatonix.

It’s quite impressive that this group turned a first place finish on the 2011 season of short-lived competition show The Sing-Off into a lasting career, with 11 studio albums and six EPs under their belt.

At least a half-dozen of those releases are Christmas-themed, and it is on one of those that this little gem appeared.

At #13, this is Pentatonix’s highest-charting song. I figure it must be one of the only a cappella songs to reach the top 20, but I couldn’t locate a definitive list.

I did, however, learn that only one song featuring no instruments other than the human voice has reached #1 on the Hot 100. Bonus points to the first commenter to guess the artist and title.