Year	Percent change (Units)
1980	33.170
1981	7.866
1982	6.747
1983	5.649
1984	8.069
1985	2.649
1986	-12.726
1987	-9.557
1988	20.386
1989	34.631
1990	4.835
1991	-0.251
1992	5.175
1993	2.385
1994	17.375
1995	25.559
1996	6.395
1997	15.064
1998	12.774
1999	-2.209
2000	1.928
2001	6.209
2002	0.051
2003	5.176
2004	-0.218
2005	11.596
2006	4.405
2007	5.979
2008	-0.853
2009	-10.673
2010	13.821
2011	2.167
2012	-5.807
2013	-3.587
2014	-7.761
2015	-1.655
2016	6.677
2017	-0.168
2018	-0.606
2019	12.504
2020	-12.978
2021	12.736
2022	-2.233
2023	-17.016
2024	31.285
2025	5.780
2026	4.653
2027	4.458
2028	4.491
2029	3.621
