BERLIN (Reuters) – Britons drove up an increase in the number of foreigners obtaining German citizenship last year, with more naturalised than in any year since Britain’s 2016 referendum vote to leave the European Union, official data showed on Wednesday.

Britain left the EU on Jan. 31. Talks aimed at setting out its future ties with the bloc have all but stalled and some Britons worry they will lose the right to live and work in Germany, Europe’s biggest economy.

Britons usually need to have lived in Germany for eight years to qualify for citizenship. Applications take more than six months to process. Britons could take up dual citizenship while Britain was still an EU member.

In 2019, some 128,900 foreigners obtained German citizenship, a 15% increase on the prior year. Almost half the increase was due to growing numbers of Britons being naturalised, the Federal Statistics Office said in a statement.

Some 14,600 Britons were naturalised in 2019, more than in the preceding two years together. In 2015, before the Brexit referendum, just 600 Britons were naturalised, the Office said.