Year	Percent change (Units)
1980	23.568
1981	2.491
1982	-6.906
1983	27.157
1984	-17.356
1985	20.406
1986	17.786
1987	10.544
1988	9.176
1989	8.469
1990	10.100
1991	19.539
1992	22.684
1993	10.140
1994	-11.567
1995	-0.046
1996	4.393
1997	2.750
1998	12.627
1999	2.597
2000	13.671
2001	15.466
2002	11.613
2003	10.038
2004	-5.453
2005	14.460
2006	6.985
2007	-0.179
2008	-0.102
2009	-5.422
2010	0.470
2011	3.855
2012	-2.901
2013	11.632
2014	8.035
2015	7.932
2016	-5.358
2017	-3.877
2018	8.421
2019	-1.696
2020	-1.000
2021	2.796
2022	4.657
2023	-11.495
2024	22.800
2025	5.487
2026	8.275
2027	6.518
2028	5.553
2029	5.828