Thanks to such acts as Britney Spears, Twenty One Pilots and Guns N’ Roses, along with soundtracks from the Guardians of the Galaxy franchise -- which boasts the year’s top two sellers -- and Netflix’s Stranger Things series, cassette tape album sales in the U.S. grew by 23 percent in 2018.

According to Nielsen Music, cassette album sales climbed from 178,000 in 2017 to 219,000 copies in 2018. While that’s a small number compared to the overall album market (141 million copies sold in 2018), that’s a sizable number for a once-dead format. In 2014, for example, cassette album sales numbered just 50,000. But, 20 years before that, back in 1994, when cassettes were still very much a hot-selling format, there were 246 million cassette albums sold that year, of an overall 615 million albums.

Cassette album releases in 2018 are still a very niche offering, with most significant titles limited to specialty reissues and unique projects. Among the top 10 selling cassette albums (see list, below) were Twenty One Pilots’ new studio album, Trench, and a reissue of Britney Spears’ debut album, …Baby One More Time.

Trench was issued on a yellow-colored cassette and sold 7,000 copies in 2018, finishing as the year’s No. 3 seller. The Trench cassette was released concurrently with the album on Oct. 5 on CD, vinyl LP and digital download formats.

Spears’ …Baby One More Time sold 4,000 cassette copies and was the No. 5 biggest seller. It was reissued on cassette for its 20th anniversary, exclusive to Target stores, as a pink-colored cassette. Spears’ …Baby One More Time was originally released in January of 1999 on CD and cassette. Of the album’s 10.6 million copies sold to date, 1.49 million are on cassette. The album debuted at No. 1 on the Billboard 200 chart, and the set's title track became Spears' first No. 1 single on the Billboard Hot 100.

For the fourth year in a row, the year’s top-selling cassette album came from the Guardians of the Galaxy film series. The best-selling title in 2018 was the Guardians of the Galaxy: Awesome Mix Vol. 1 soundtrack (24,000 sold). It was released in 2014 and served as the companion album to the first Guardians of the Galaxy movie. It was also the top seller in 2015 and 2016. The cassette continues to do robust business, thanks to its strong link to the first film. The cassette is a replica of the oft-played mixtape seen in the movie, and the set’s music is heard throughout the film.

In 2017, the movie’s sequel soundtrack took over as the year’s best-selling cassette album, as Guardians of the Galaxy, Vol. 2: Awesome Mix Vol. 2 was tops.

In 2018, Vol. 2 finished as the No. 2 seller (19,000). Another Guardians-related cassette, Guardians of the Galaxy: Cosmic Mix, Vol. 1, is the No. 6 seller of the year (3,000). Cosmic is the soundtrack to the first season of the animated Guardians of the Galaxy TV series.

Other titles among the top 10 selling cassette albums of 2018: Guns N’ Roses' 30th reissue of their debut album, Appetite for Destruction (No. 7 with 3,000); Metallica’s reissue of The $5.98 EP: Garage Days Re-Revisited (No. 8; 3,000); Elvis Presley’s new inspirational compilation Where No One Stands Alone (No. 9; 2,000); and Wu-Tang Clan’s 25th-anniversary reissue of their debut set, Enter the Wu-Tang (36 Chambers) (No. 10; 2,000).

In total for 2018, there were 28 albums that sold at least 1,000 copies on cassette -- up from just 17 in 2017. (Though, there were 25 titles that sold at least 1,000 in 2016.)