Billboard began a Top 40 Airplay Monitor chart on October 20, 1984. It listed the 30 most-played songs (including album tracks) on top-40 radio stations. Stevie Wonder's I Just Called To Say I Love You was number one. The chart expanded to 40 positions in May 1986 and 75 positions in December 1990. The chart is now called Radio Songs and includes airplay data from pop, rock, adult contemporary, R&B, hip-hop, Christian and jazz stations.
The Goo Goo Dolls' Iris debuted at #66 on the April 18 1998 airplay chart and went to number one on the August 8 1998 chart. Beginning with the December 5 1998 Hot 100, airplay-only songs – which are not released as a commercially available single – are eligible for the Hot 100. In its 18th and final week at number one on the airplay chart, Iris debuted on the December 5 1998 Hot 100 at #9. Since June 1998, Billboard had compiled a weekly Hot 100 that included airplay-only songs. Those were considered "test charts" and were not published. The "last week" and "weeks on" columns of the December 5 1998 Hot 100 were adjusted to include data from the test charts. Iris was not shown as a debut, even though it really was. It was shown as dropping from #7 the previous week and was in its 30th week on the Hot 100. It remained on the chart until March 1999.