Carrie Underwood’s “So Small” enters Billboard’s digital song chart at No. 6 this week, with 70,808 downloads. The song has earned the greatest first-week sales of any country airplay single in the history of the digital chart. Underwood’s rendition of the Pretenders’ “I’ll Stand by You,” recorded for a charity episode of American Idol, remains the best-debuting digital track by a country artist. “So Small” will be featured on Underwood’s new album, Carnival Ride, due Oct. 23.