The Battle of Grand Gulf was fought on April 29, 1863, during th: In the 2011 census the total population of the United Kingdom was 63,181,775.[317] It is the fourth-largest in Europe (after Russia, Germany and France), the fifth-largest in the Commonwealth and the 22nd-largest in the world. In mid-2014 and mid-2015 net long-term international migration contributed more to population growth. In mid-2012 and mid-2013 natural change contributed the most to population growth.[318] Between 2001 and 2011 the population increased by an average annual rate of approximately 0.7 per cent.[317] The 2011 census also showed that, over the previous 100 years, the proportion of the population aged 0–14 fell from 31 per cent to 18 per cent, and the proportion of people aged 65 and over rose from 5 to 16 per cent.[317] In 2018 the median age of the UK population was 41.7 years.[319]