Latin Pop Airplay (also referred to as Latin Pop Songs) is a record chart published on Billboard magazine. It features Latin music information from pop music usually in Spanish. It was established by the magazine on October 8, 1994 with Mañana by Cristian Castro being the first song to reach number-one. This chart features only singles or tracks and like most Billboard charts, is based on airplay; the radio charts are compiled using information tracked by from Nielsen Broadcast Data Systems (BDS), which electronically monitors radio stations in more than 140 markets across the United States. The audience charts cross-reference BDS data with listener information compiled by the Arbitron ratings system to determine the approximate number of audience impressions made for plays in each daypart.