Kenya's leading mobile money transfer service M-Pesa was the top source of revenue for Vodafone Group PLC (VOD) through the U.K. mobile operator's investment in Safaricom Ltd. (SAF.NR) in fiscal 2011, the East African weekly newspaper reports Monday.

Safaricom's latest annual report shows Vodafone earned $21 million through its Kenyan subsidiary, with $15.6 million coming from M-Pesa in license fees, the weekly reports.

The mobile money transfers account for 2% of Safaricom's total revenue of $1 billion, the weekly says.

The strong growth in M-Pesa subscriber numbers has helped Safaricom hold on to some of its customers at a time when mobile service providers in Kenya have been slashing call rates to expand their subscriber base, the daily reports.

M-Pesa enables mobile subscribers to send and receive money from other subscribers.

Safaricom currently has over 17 million subscribers in Kenya, commanding a share of more than 70% of the Kenyan mobile market, the weekly reports.

Safaricom is also diversifying into data services due to the stiff competition in voice service rates.

Full story: http://www.theeastafrican.co.ke/

-By George Mwangi, contributing to Dow Jones Newswires; +254 735 781 853; gmwangi0@gmail.com