LUANDA (Reuters) - Angola s ruling MPLA party has won a general election by taking 61.07 percent of the vote, the electoral commission said on Wednesday, making Jo o Louren o the next president of sub-Saharan Africa s third-largest economy. He will replace Jose Eduardo dos Santos, who steps down after 38 years at the helm but will continue as head of the People s Movement for the Liberation of Angola (MPLA). The main opposition National Union for the Total Independence of Angola (UNITA) took 26.67 percent, with the smaller opposition party CASA-CE winning 9.44 percent.  Mission accomplished,  Louren o told supporters at his party s headquarters in Luanda.  We ll produce a better future for the country and the people of Angola,  he said in his first comments as president-elect. He is expected to take office on Sept. 21. UNITA, which has repeatedly complained that the electoral process has been non-transparent and illegal, declined to comment after the results on Wednesday. A spokesman told Reuters a statement will be made on Thursday. UNITA has previously said it will appeal the results. Speaking earlier on Wednesday, the spokeswoman for the National Electoral Commission Julia Ferreira rejected the opposition s complaints as having a  lack of clarity and objectivity , adding sufficient proof had not been presented. Electoral observers have said the vote on Aug 23 was reasonably free and fair. The head of the African Union s observation mission, Jose Maria Neves, congratulated Angola on a poll he said served as a  reference for the continent . Speaking before announcing definitive election results, President of the National Electoral Commission Andr  da Silva Neto asked the parties to accept the election results. On the streets of Luanda, cheering and the honking of horns was heard as residents celebrated another electoral win for the MPLA, which has maintained an unbroken hold on power since Africa s second-largest crude producer gained independence from Portugal in 1975. Louren o will be only the country s third president in that time. A quiet 63-year-old more used to army barracks and the closed doors of party politics than the public spotlight, he has denied he will remain in the shadow of his predecessor dos Santos. Louren o has promised to kick-start the economy and has not ruled out deals with the World Bank and International Monetary Fund to help restructure it. Angola imports everything from washing powder to long-life milk at huge cost. MPLA will have 150 lawmakers, giving them the two-thirds parliamentary majority needed to pass any form of legislation. 