Citi strategists said on Monday that if the U.K. leaves the European Union (Brexit), consumer prices in the U.K. will rise to 3% - 4% for several years after a "Brexit". The pound will depreciate by 15% - 20%, according to Citi strategists. Citi strategists noted that the annual U.K. GDP would be reduced by 1% - 1.5% in 2017 - 2019.