Year	Percent change (Units)
1980	13.530
1981	17.300
1982	24.400
1983	52.500
1984	25.100
1985	24.400
1986	27.300
1987	32.500
1988	85.700
1989	54.200
1990	49.500
1991	49.000
1992	60.200
1993	32.000
1994	25.383
1995	22.774
1996	25.527
1997	30.700
1998	43.400
1999	60.700
2000	91.005
2001	22.422
2002	9.361
2003	6.072
2004	1.949
2005	3.132
2006	2.869
2007	3.319
2008	8.832
2009	4.312
2010	3.328
2011	5.409
2012	4.164
2013	2.701
2014	3.667
2015	3.380
2016	1.120
2017	-0.197
2018	0.266
2019	-0.065
2020	-0.933
2021	1.941
2022	3.737
2023	1.350
2024	1.530
2025	1.480
2026	1.510
2027	1.540
2028	1.540
2029	1.540