Year	Percent
1990	45.666
1991	45.729
1992	45.227
1993	44.91
1994	44.883
1995	44.662
1996	44.34
1997	43.966
1998	43.646
1999	43.342
2000	43.099
2001	43.084
2002	42.832
2003	42.942
2004	42.954
2005	42.498
2006	41.963
2007	41.537
2008	41.391
2009	41.245
2010	39.368
2011	41.5
2012	43.7
2013	42.5
2014	43.248
2015	44
2016	43.648
2017	43.581
2018	43.514
2019	43.447
2020	43.38
2021	43.313
2022	43.246
2023	43.179
2024	43.112
2025	43.045
2026	42.978
2027	42.911
2028	42.844
2029	42.777
2030	42.711