Year Sterling 1997-12-31 7950 1998-12-31 8660 1999-12-31 9955 2000-12-31 9358 2001-12-31 11166 2002-12-31 11310 2003-12-31 12768 2004-12-31 12754 2005-12-31 12268 2006-12-31 12530 2007-12-31 13878 2008-12-31 12969 2009-12-31 14393 2010-12-31 12738 2011-12-31 14575 2012-12-31 15355 2013-12-31 17750 2014-12-31 22456 2015-12-31 21306 2016-12-31 22475 2017-12-31 23696 2018-12-31 26175 2019-12-31 27612 2020-12-31 42187 2021-12-31 40546 2022-12-31 35014 2023-12-31 31756