Year	total route-km
1980	494655.9
1981	494444.9
1982	496343.9
1983	497349.9
1984	497731.4
1985	501633.7
1986	501942.2
1987	501289.85
1988	501993.42
1989	505306.77
1990	511234.018483871
1991	512185.855483871
1992	511278.455483871
1993	511170.915483871
1994	511655.715483871
1995	510194.905483871
1996	511738.257589134
1997	516472.145483871
1998	513608.445483871
1999	513942.775483871
2000	520066.935483871
2001	513823.935483871
2002	516841.935483871
2003	514765.935483871
2004	514997.935483871
2005	544643.935483871
2006	545379.935483871
2007	548975.935483871
2008	546442.935483871
2009	538033.935483871
2010	540402.935483871
2011	542191.935483871
2012	541420.935483871
2013	540571.375483871
2014	545195.935483871
2015	545203.755483871
2016	545644.085483871