Latin Regional Mexican Airplay

Regional Mexican Airplay (also referred to as Regional Mexican Songs) is a record chart published on Billboard magazine. It was established by the magazine on October 8, 1994 with La Niña Fresa by Banda Z being the first song to reach number-one. It features Latin music information from different genres including Mariachi, Norteño, Banda and Duranguense, which are frequently named as Regional Mexican. 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.

...
Wikipedia