Year	total route-km
1980	295980.2
1981	295658.2
1982	297250.2
1983	298404.2
1984	298259.2
1985	300481.2
1986	301147.7
1987	300951.7
1988	301584.7
1989	305216.7
1990	312306.363
1991	309996.7
1992	311738.3
1993	311584.1
1994	311911.9
1995	310343
1996	317755.862105263
1997	318427
1998	318218
1999	318431
2000	321785
2001	321620
2002	321300
2003	319342
2004	319609
2005	349887
2006	351242
2007	354980
2008	353219
2009	345999
2010	347702
2011	349085
2012	348896
2013	348703.94
2014	350552
2015	350647.59
2016	351313.15