Year	Percent change (Units)
1980	-13.427
1981	16.142
1982	32.697
1983	10.473
1984	14.496
1985	7.780
1986	-12.803
1987	6.048
1988	3.579
1989	25.336
1990	-7.561
1991	13.000
1992	17.800
1993	59.800
1994	22.300
1995	-1.500
1996	15.200
1997	-6.939
1998	-4.031
1999	-0.401
2000	20.588
2001	7.114
2002	-2.158
2003	2.397
2004	31.436
2005	16.360
2006	18.390
2007	16.411
2008	22.439
2009	9.356
2010	13.412
2011	16.694
2012	29.851
2013	15.255
2014	15.345
2015	-13.677
2016	-0.807
2017	2.603
2018	7.574
2019	-1.997
2020	-19.922
2021	-3.050
2022	8.075
2023	0.259
2024	-0.366
2025	0.916
2026	4.547
2027	11.582
2028	7.992
2029	7.065