Year	Percent change (Units)
1980	1.423
1981	8.282
1982	13.485
1983	6.664
1984	4.708
1985	-0.759
1986	2.916
1987	6.051
1988	5.808
1989	12.144
1990	4.331
1991	2.668
1992	14.722
1993	11.250
1994	12.563
1995	13.133
1996	6.359
1997	11.495
1998	3.889
1999	4.870
2000	16.038
2001	2.280
2002	17.205
2003	12.382
2004	15.147
2005	11.520
2006	10.262
2007	17.872
2008	1.790
2009	-2.139
2010	26.203
2011	13.598
2012	-0.125
2013	6.781
2014	5.557
2015	-6.299
2016	7.806
2017	5.459
2018	5.331
2019	-4.609
2020	-7.513
2021	21.810
2022	0.797
2023	-2.759
2024	3.775
2025	4.204
2026	3.821
2027	3.711
2028	3.630
2029	3.506