Year	Percent (Units)
1992	4.848
1993	4.341
1994	3.681
1995	3.405
1996	3.161
1997	3.080
1998	2.837
1999	2.915
2000	3.062
2001	3.141
2002	3.200
2003	3.302
2004	3.360
2005	3.415
2006	3.510
2007	3.618
2008	3.700
2009	3.425
2010	3.401
2011	3.401
2012	3.448
2013	3.533
2014	3.425
2015	3.143
2016	3.038
2017	3.112
2018	3.090
2019	3.072
2020	3.080
2021	3.068
2022	2.933
2023	2.947
2024	2.948
2025	2.908
2026	2.855
2027	2.803
2028	2.754
2029	2.706