MTN Group added 4.1 million more users to its books in the quarter ended March‚ taking its total user base to 227.5 million subscribers. Data revenue increased 16.7% in the quarter‚ when compared to the first quarter last year. Data now contributes 21% of the group’s revenue‚ said the company‚ which continued to expand its 3G and LTE networks during the period.Weaker economic environments in both the company’s major markets of Nigeria and South Africa negatively impacted the quarterly results‚ said MTN.The price of oil‚ the biggest economic driver in Nigeria‚ halved last year‚ reducing the economic growth of Africa’s biggest single economy.In South Africa the economy grew at 1.5% last year‚ eroding the disposable income of cellphone users.Whereas the company’s 24.8 million South African subscribers spent on average R95.21 on their cellphones in the first quarter last year‚ the 28 million users it now has on its books spent on average R87.16 in the quarter to March.In Nigeria the 57.2 people that used MTN’s cellphone services last year spent on average 1 177.82 naira while the 61.1 million people now spend on average 1 102.59 naira. One SA rand buys 16.5 naira.Measured in US dollars‚ MTN Nigeria’s average revenue per user declined from the $7‚21 last year’s first quarter‚ to $5‚68 this first quarter. South Africa’s also fell by $2 to $7.45 this year.The company has maintained its target of adding 17.5 million customers this year. – RDM NewsWire, Business Day..