Year	Percent change (Units)
1980	10.769
1981	15.989
1982	-37.662
1983	-20.105
1984	12.151
1985	-7.133
1986	9.300
1987	21.200
1988	12.949
1989	29.560
1990	1.800
1991	9.300
1992	25.700
1993	12.800
1994	6.500
1995	24.400
1996	12.070
1997	11.988
1998	6.989
1999	-14.471
2000	13.535
2001	1.902
2002	1.142
2003	10.190
2004	19.906
2005	22.703
2006	12.781
2007	16.738
2008	15.963
2009	-20.105
2010	31.127
2011	17.385
2012	6.067
2013	1.074
2014	-6.776
2015	-0.658
2016	1.190
2017	4.901
2018	8.596
2019	-2.128
2020	-9.776
2021	35.448
2022	-2.124
2023	-13.168
2024	4.027
2025	4.465
2026	2.979
2027	2.545
2028	2.567
2029	2.614