Through the end of the year, Chart Beat is looking back at the biggest achievements on Billboard's charts in 2010.
Mariah Carey's "Oh Santa!" dashes 12-1 in just its second week on Adult Contemporary, marking the quickest coronation since the survey adopted Nielsen BDS-monitored radio airplay data in 1993. Carey collects her seventh Adult Contemporary No. 1 and first since "One Sweet Day," with Boyz II Men, led for 13 weeks in 1995-96