The Battle of Grand Gulf was fought on April 29, 1863, during th: Immigration is now contributing to a rising UK population,[378] with arrivals and UK-born children of migrants accounting for about half of the population increase between 1991 and 2001. According to official statistics released in 2015, 27 per cent of UK live births in 2014 were to mothers born outside the UK.[379] The ONS reported that net migration rose from 2009 to 2010 by 21 per cent to 239,000.[380]