Year	Percent change (Units)
1980	14.700
1981	13.849
1982	-0.942
1983	12.076
1984	19.100
1985	5.463
1986	14.585
1987	28.409
1988	21.531
1989	8.258
1990	8.183
1991	14.423
1992	17.542
1993	12.378
1994	9.435
1995	9.913
1996	5.648
1997	4.812
1998	-4.458
1999	4.519
2000	16.916
2001	-1.051
2002	8.563
2003	13.105
2004	16.106
2005	12.168
2006	10.175
2007	8.241
2008	3.520
2009	-9.121
2010	17.570
2011	4.808
2012	3.205
2013	7.818
2014	0.973
2015	-1.371
2016	0.684
2017	5.845
2018	3.654
2019	-6.146
2020	-6.681
2021	17.037
2022	-12.535
2023	-6.533
2024	5.491
2025	4.152
2026	3.935
2027	3.976
2028	3.912
2029	3.983