The answer is more and more. Electric bicycles account of a third of bicycles sold in Germany, more than 40% of those sold in the Netherlands and a majority of all bicycles sold in Belgium.
So many are being sold, in fact, that it's hard to keep track. In 2017, industry estimates were that 50 million electric bicycles would be sold in the European Union between then and 2030. It's now estimated that 150 million will be sold between now and then.