Year	Percent change (Units)
1980	21.308
1981	9.883
1982	6.079
1983	4.900
1984	8.076
1985	-4.021
1986	10.913
1987	13.301
1988	26.659
1989	9.602
1990	14.495
1991	7.180
1992	7.469
1993	18.549
1994	16.464
1995	22.908
1996	10.028
1997	11.230
1998	-8.444
1999	9.412
2000	20.019
2001	-6.823
2002	5.540
2003	9.889
2004	22.623
2005	11.573
2006	10.300
2007	7.464
2008	10.876
2009	-9.946
2010	16.307
2011	5.688
2012	2.582
2013	6.513
2014	2.769
2015	3.381
2016	0.183
2017	8.241
2018	7.824
2019	-0.079
2020	-1.666
2021	9.566
2022	3.300
2023	1.017
2024	8.151
2025	5.216
2026	4.619
2027	4.396
2028	2.797
2029	2.699