Year	% of revenue
1973	4.638323722482141
1974	4.17919898686085
1975	3.5755148741418767
1976	3.553892915595043
1977	2.743045076446662
1978	2.5162048643443917
1979	2.5306806602877714
1980	2.4895545130487244
1981	3.305849866393444
1982	2.7185440392476203
1983	2.9259244685912567
1984	3.122033540765754
1985	2.2975367087762915
1991	1.8760503293493573
1993	2.2767217370143036
1994	2.947938069780086
1995	2.1736914530350133
1996	2.06436141877326
1997	1.7976145644644508
1998	1.509483933096758
1999	1.3397882556793352
2000	1.2573941021179758
2001	1.253048534624857
2002	1.3354063724654968
2003	1.25883087874077
2004	0.5964796444019937
2005	1.0809421966122073
2007	0.7937271279591566
2010	1.0097015384695043
2011	0.9491232240096175
2012	0.9420139052796763
2013	0.7525011363998828
2014	0.8384586064014733