Adult Contemporary is a chart published by Billboard ranking the top-performing songs in the United States in the adult contemporary music (AC) genre. In 2009, seven different songs topped the chart in 52 issues of the magazine, based on weekly airplay data from radio stations compiled by Nielsen Broadcast Data Systems.. At the start of the year, the number one position was held by Faith Hill.
This is a list of songs that have peaked at number one on the Billboard Hot 100 and the magazine's national singles charts that preceded it. Introduced in 1958, the Hot 100 is the pre-eminent singles chart in the United States, currently monitoring the most popular singles in terms of popular radio play, single purchases and online streaming.
Singer Mariah Carey (born March 27, 1970) burst onto the pop charts in 1990, wowing fans and critics alike with a powerful five-octave vocal range and catchy hits that shot to No. 1. During the next two decades, Carey would record a total of 18 songs that reached the top of .