LUSAKA — Zambia's ruling party candidate Edgar Lungu has a slim lead after most votes have been counted in a presidential poll, the electoral commission said on Saturday, with the final tally due later in the day. With no reliable opinion polls in the southern African state, experts have struggled to call a winner in the contest to succeed Michael Sata, who died in office in October aged 77. Patriotic Front candidate Lungu led rival Hakainde Hichilema 48.4 percent to 46.7 percent according to the latest results from 141 out of 150 constituencies released by the Electoral Commission of Zambia. However, with another election scheduled for late next year when Sata's term had been due to end, the winner will have little time to turn around a stuttering economy in one of Africa's most promising frontier markets. Zambia has averaged 6-7 percent growth as the mining sector boomed but that slowed to 5.5 percent last year, the International Monetary Fund said, and could ease further with the price of copper reaching a 6-year low this month. Defense and Justice Minister Lungu, a former lawyer with a laid-back, populist style, has used his campaign to tap into the grassroots support of his predecessor Sata, promising voters cheaper food and fuel. Hichilema, one of Zambia's wealthiest businessmen, has said that if he wins, he will draw on his experience in the private sector to attract foreign investment and diversify an economy, where copper accounts for 70 percent of export earnings. Turnout for the election was around 32 percent as heavy rains disrupted voting across much of the landlocked country. Observers said the election was conducted in a fair manner. — Reuters