Year	% of revenue
1973	2.1765314316158286
1974	2.11919111108348
1975	3.091578114790733
1976	2.006043850061081
1977	1.863683426349147
1978	1.5585669459673805
1979	1.5003931161002868
1980	1.544757622917745
1981	1.5104966717869894
1982	1.4670171128189078
1983	1.367451141498915
1984	1.387399610477711
1985	1.0882963918635267
1986	1.0817959558682309
1987	1.170154148495579
1988	1.5617426894286166
1990	1.595338198563744
1991	1.4493059160451482
1992	2.0565378167118573
1993	2.0816831836305845
1994	2.4779928126339392
1995	1.7348894003954778
1996	1.5562305030578256
1997	1.447961387696328
1998	1.3392245183402283
1999	1.2417386191940876
2000	1.1559495922823175
2001	1.253048534624857
2002	1.3612781200139477
2003	1.2420471069593804
2004	0.4362591667820377
2005	1.0834129485699042
2006	1.0575435471576637
2007	0.6124823146843361
2008	0.9577419751616295
2009	0.9915449630909724
2010	1.0097015384695043