Japan will launch a music download chart next month, joining several other countries that already have done so.

The Recording Industry Association of Japan (RIAJ) will begin publishing the chart on the 20th of each month, it said on Wednesday. The chart will be compiled from data supplied by mobile phone ringtone and music download services.

Legal music downloads have been offered in Japan for several years and quickly became popular with mobile phone users although computer users were slower on the uptake.

Computer services only became popular when Apple launched the iTunes Music Store in Japan last year. At about the same time a rival offering from Sony and other majors revamped its service and started to more actively promote downloads to users of Windows Media-compatible players.

Last week the RIAJ said there were 90.5 million downloads made during the April to June period in Japan. Of those just under 6 million were through sites like iTunes Music Store and the remainder were through mobile phone services.