Year	Percent change (Units)
1980	-10.200
1981	2.400
1982	-7.300
1983	-16.200
1984	10.400
1985	-1.900
1986	-14.800
1987	42.200
1988	1.700
1989	0.200
1990	-8.925
1991	16.208
1992	34.768
1993	7.697
1994	4.437
1995	8.741
1996	-5.500
1997	32.555
1998	30.740
1999	-0.549
2000	14.671
2001	0.444
2002	5.736
2003	-1.184
2004	6.148
2005	-0.602
2006	6.447
2007	7.827
2008	-5.729
2009	-7.706
2010	10.004
2011	6.970
2012	2.777
2013	4.566
2014	3.370
2015	3.648
2016	0.942
2017	2.825
2018	3.927
2019	4.857
2020	-5.757
2021	19.486
2022	4.361
2023	5.162
2024	5.600
2025	5.920
2026	5.936
2027	6.016
2028	5.790
2029	5.850
