Year Sterling 1997-12-31 2321 1998-12-31 2322 1999-12-31 2406 2000-12-31 2694 2001-12-31 2819 2002-12-31 2945 2003-12-31 2917 2004-12-31 3322 2005-12-31 3295 2006-12-31 3531 2007-12-31 4008 2008-12-31 4063 2009-12-31 4192 2010-12-31 5509 2011-12-31 5393 2012-12-31 4770 2013-12-31 4445 2014-12-31 5078 2015-12-31 5325 2016-12-31 6479 2017-12-31 6573 2018-12-31 7182 2019-12-31 7074 2020-12-31 11458 2021-12-31 11336 2022-12-31 10994 2023-12-31 11228