Telkom South Africa has reported group operating revenue of ZAR32.5 billion (USD3.2 billion) for the twelve months ending 31 March 2013, down 1.7% year-on-year. The company recorded a 5% increase in data revenues on the back of its ADSL subscriber base growing 5.2% to 870,505. However, this failed to offset a 4.8% drop in voice telephony sales due to continued mobile substitution, coupled with a 13.9% decline in interconnection revenues. EBITDA slipped almost 17% year-on-year to ZAR7.1 billion as workforce reduction expenses – including voluntary severance and early retirement packages – soared from ZAR29 million to ZAR753 million. Operating income, meanwhile, plunged from a profit of ZAR2.4 billion in the year ending 31 March 2012 to a loss of more than ZAR11 billion, primarily due to a ZAR12 billion impairment of legacy assets. Mobile subscribers increased by 3.4% to just over 1.5 million, but monthly ARPU over the year dropped by more than 17% to ZAR61.5 (USD6.1).