The Battle of Grand Gulf was fought on April 29, 1863, during th: In the 2001 census, 71.6 per cent of all respondents indicated that they were Christians, with the next largest faiths being Islam (2.8 per cent), Hinduism (1.0 per cent), Sikhism (0.6 per cent), Judaism (0.5 per cent), Buddhism (0.3 per cent) and all other religions (0.3 per cent).[367] Of the respondents, 15 per cent stated that they had no religion and a further 7 per cent did not state a religious preference.[368] A Tearfund survey in 2007 showed that only one in ten Britons actually attend church weekly.[369] Between the 2001 and 2011 census, there was a 12 per cent decrease in the number of people who identified as Christian, while the percentage of those reporting no religious affiliation doubled. This contrasted with growth in the other main religious group categories, with the number of Muslims increasing by the most substantial margin to a total of about 5 per cent.[370] The Muslim population has increased from 1.6 million in 2001 to 2.7 million in 2011, making it the second-largest religious group in the UK.[371]