Year	Number
1996	1.67031967639923
1998	1.73684322834015
2000	1.59273290634155
2002	1.57149362564087
2003	1.49655044078827
2004	1.51924753189087
2005	1.73055720329285
2006	1.53167414665222
2007	1.55425381660461
2008	1.49149310588837
2009	1.33218801021576
2010	1.34430372714996
2011	1.45015203952789
2012	1.53906953334808
2013	1.50458896160126
2014	1.59949147701263
2015	1.52147006988525
2016	1.32980799674988
2017	1.26685953140259
2018	1.37823557853699
2019	1.2576550245285
2020	1.43574929237366
2021	1.4654449224472
2022	1.54913818836212