Year Sterling (millions) 2011-12-31 19936 2012-12-31 17525 2013-12-31 15816 2014-12-31 19991 2015-12-31 18446 2016-12-31 19863 2017-12-31 19499 2018-12-31 20976 2019-12-31 20458 2020-12-31 23735 2021-12-31 21222 2022-12-31 21514 2023-12-31 19237