Year	% of total
1970	7.131529760121919
1971	7.355189946388424
1972	6.654193080823051
1973	6.401555445243794
1974	6.78633130029881
1975	7.0820935696171015
1976	6.328258737184882
1977	6.399286567396236
1978	6.663743760717694
1979	5.778154411722991
1980	5.722630269786918
1981	5.8786143625537655
1982	5.904350585578873
1983	5.5519551687947155
1984	5.976503796201836
1985	6.509480948428294
1986	6.991057393763316
1987	6.769163812362701
1988	7.136092336426195
1989	6.837154894659853
1990	3.6011080332409975
1991	3.4759358288770055
1992	3.3419023136246784
1993	3.4739454094292808
1994	3.3816425120772946
1995	3.3175355450236967
1996	3.3707865168539324
1997	3.112033195020747
1998	3.2397408207343417
1999	3.488372093023256
2000	3.950617283950617
2001	3.0303030303030303
2002	3.3472803347280333
2003	3.6093418259023355
2004	3.4552845528455287
2005	3.829787234042553
2006	3.75
2007	4.194260485651214
2008	3.861788617886179