Year	total route-km
1980	160437.2
1981	160258.2
1982	160255.2
1983	160273.2
1984	160252.2
1985	161922.2
1986	161833.2
1987	161920.2
1988	162154.2
1989	162642.2
1990	169210.2
1991	171789.6
1992	173450.2
1993	172588
1994	172659
1995	172376
1996	172426.842105263
1997	171711
1998	171176
1999	171043
2000	170827
2001	170284
2002	170391
2003	170101
2004	169492
2005	170169
2006	170247
2007	169028
2008	169425
2009	170400
2010	171384
2011	171109
2012	170321
2013	170129.6
2014	171414
2015	171122.38
2016	172585.21