GABORONE, Nov 30 (Reuters) - Sales of rough diamonds by Debswana Diamond Company jumped 73% in the first nine months of 2021, statistics released by the Bank of Botswana showed on Tuesday, driven by the reopening of U.S. and China"s consumer markets. Debswana, a joint venture between Anglo American (AAL.L) business De Beers and the Botswana government, sells 75% of its output to De Beers, with the balance taken up by state-owned Okavango Diamond Company. Debswana sales fell by 30% in 2020 as the COVID-19 pandemic hit demand while global travel restrictions hurt trading. Botswana closed its borders for eight months last year in an effort to curb the spread of the virus, effectively locking out foreign buyers from centres such as Mumbai, Antwerp and China, who traditionally travel to Gaborone 10 times a year to view and buy diamonds from De Beers. Since mid-2020 De Beers has shifted some of its rough viewings to places closer to international diamond centres, such as Antwerp, to cater for customers unable to travel to Gaborone. According to data published by the central bank, exports of diamonds from Debswana stood at $2.589 billion in the first nine months of the year compared with $1.498 billion in the same period last year. Botswana makes about 30% of its revenue and 70% of its foreign exchange earnings from diamonds. While it has taken measures to diversify its dependence on a single commodity, diamond sales continue to be its main revenue earner. De Beers" sales softened by 4% in the current sales period, which ended last week, as Indian manufacturers closed factories ahead of the Diwali festival, though the company said diamond jewellery demand remained strong in the United States.