Year	Percent change (Units)
1980	5.000
1981	51.100
1982	6.600
1983	12.500
1984	-12.400
1985	-3.700
1986	1.900
1987	22.700
1988	6.336
1989	11.600
1990	21.400
1991	15.900
1992	8.800
1993	5.400
1994	20.300
1995	17.814
1996	10.623
1997	0.703
1998	-25.611
1999	-32.913
2000	25.495
2001	-10.439
2002	3.126
2003	4.083
2004	14.818
2005	23.946
2006	-2.312
2007	7.688
2008	17.608
2009	-18.228
2010	17.608
2011	18.258
2012	15.741
2013	1.050
2014	0.286
2015	-7.457
2016	0.955
2017	10.712
2018	14.486
2019	-9.654
2020	-14.856
2021	15.164
2022	8.885
2023	-2.150
2024	16.199
2025	12.806
2026	9.298
2027	7.253
2028	7.423
2029	7.414