Year	Percent
1990	49.894
1991	49.33
1992	48.656
1993	48.35
1994	48.48
1995	47.968
1996	47.457
1997	46.946
1998	46.436
1999	45.926
2000	45.417
2001	44.91
2002	44.403
2003	43.898
2004	43.393
2005	42.89
2006	42.389
2007	41.889
2008	41.391
2009	40.895
2010	40.4
2011	41.08
2012	41.764
2013	41.193
2014	40.625
2015	40.059
2016	40.8
2017	40.551
2018	40.301
2019	40.052
2020	39.803
2021	39.553
2022	39.304
2023	39.055
2024	38.805
2025	38.556
2026	38.306
2027	38.057
2028	37.808
2029	37.558
2030	37.309