Year	Percent
1980	29.37529
1981	29.37549
1982	29.37684
1983	29.37551
1984	29.37649
1985	29.37622
1986	29.37623
1987	29.37656
1988	29.37598
1989	29.37585
1990	29.37591
1991	29.37656
1992	29.37654
1993	29.37585
1994	29.37627
1995	29.37647
1996	29.37611
1997	29.376
1998	29.37584
1999	29.37636
2000	29.37632
2001	29.37629
2002	29.37601
2003	29.37613
2004	29.37602
2005	29.37627
2006	29.37634
2007	28.95665
2008	29.13892
2009	30.03301
2010	30.41606
2011	30.56422
2012	30.17296
2013	30.78986
2014	30.01145
2015	30.59863
2016	31.36847
2017	31.89889
2018	33.72015
2019	35.6201
2020	35.7974
2021	35.51165
2022	36.4122