Year	Percent change (Units)
1980	9.400
1981	21.207
1982	100.830
1983	22.118
1984	75.649
1985	15.107
1986	17.793
1987	25.230
1988	60.200
1989	251.100
1990	585.800
1991	70.300
1992	43.000
1993	35.300
1994	32.200
1995	27.875
1996	19.900
1997	14.900
1998	11.800
1999	7.300
2000	10.100
2001	5.500
2002	1.900
2003	0.735
2004	3.538
2005	2.210
2006	1.197
2007	2.472
2008	4.342
2009	3.785
2010	2.590
2011	4.226
2012	3.727
2013	1.117
2014	0.105
2015	-0.924
2016	-0.677
2017	1.969
2018	1.767
2019	2.244
2020	3.379
2021	5.124
2022	14.360
2023	11.424
2024	5.014
2025	4.966
2026	3.582
2027	2.900
2028	2.500
2029	2.500