Sales from Apple's iTunes digital download service have not kept pace with strong sales of iPod players, according to analyst company Forrester Research.

Apple doesn't reveal revenue from iTunes, but Forrester conducted an analysis of debit and credit transactions over a 27-month period.

Almost 60 million iPods have been sold since 2001.
(Jeff Chiu/Associated Press)

The results released Monday show that since January, monthly revenue from iTunes sales fell by 65 per cent. The average transaction size declined by 17 per cent.

Apple's iTunes holds more than a 70 per cent share of the digital download market, but the Forrester study suggests this has more to do with nearly 60 million iPods sold since 2001 than a rush for iPod users to use the service.

Since the introduction of the iTunes Store in 2003, Apple is averaging about 20 iTunes tracks for each iPod sold, suggesting consumers aren't sold on the value of digital music, according to study author Josh Bernoff.

However, the study does say the ratio of iTunes to iPods is slowly growing. The study also doesn't take into account broken or unused iPods in its calculation of the ratio.

A report from Akamai's Net Usage Index for Digital Music released Monday revealed a more optimistic view for music downloading services in general.

Akamai reported digital downloading sites collectively experience a daily peak of more than half a million visitors per minute.

The Akamai study also suggests downloaders in general remain active, with 76 per cent of respondents spending $1-$5 on music downloads every week.

Akamai based its finding on a survey of 200 people aged 19 to 68.