FRANKFURT, Sept 20 (Reuters) - German crude oil import volumes fell 7.9% in the first seven months of 2021 year-on-year as the COVID-19 pandemic and related lockdowns hit industry, but the bill was up by nearly a third due to higher prices, official data showed on Monday. Oil volumes in January through July fell to 44.9 million tonnes from 48.7 million in the same months of 2020, statistics from the BAFA foreign trade office showed. Russia accounted for 33.6% of Germany’s oil imports in the period, followed by 19.1% from the British and Norwegian North Sea, while imports from members of the Organization of the Petroleum Exporting Countries (OPEC) contributed 16.0%. The rest was shared among other sources including, prominently, the United States and Kazakhstan. Germany spent 17.9 billion euros ($20.98 billion) on crude imports in the period, 29.7% more than a year earlier. Brent crude prices have gained 43% this year, supported by supply cuts made by OPEC and allies, and some demand recovery after the COVID-19-induced collapse last year. In the German Jan-July statistics, average oil prices paid for each tonne at the national border had been 40.7% higher than a year earlier at 398.65 euros per tonne, BAFA said.