Year	total route-km
1980	439399.9
1981	439146.9
1982	441037.9
1983	442244.9
1984	442726.4
1985	446263.7
1986	446377.2
1987	446432.85
1988	447172.42
1989	450975.77
1990	457387.018483871
1991	458200.855483871
1992	459328.455483871
1993	458574.615483871
1994	459672.415483871
1995	458686.605483871
1996	461675.597589134
1997	466077.145483871
1998	463213.445483871
1999	462825.275483871
2000	470016.935483871
2001	466494.935483871
2002	469720.935483871
2003	467965.935483871
2004	468859.935483871
2005	498662.935483871
2006	500325.935483871
2007	503931.935483871
2008	501014.935483871
2009	493379.935483871
2010	495806.935483871
2011	497404.935483871
2012	496732.935483871
2013	496540.375483871
2014	501300.935483871
2015	501764.755483871
2016	502285.085483871