Year	total route-km
1980	21208
1981	21099
1982	21311
1983	21379
1984	21491
1985	23275
1986	23503
1987	23673
1988	24024
1989	23796
1990	23412
1991	23177
1992	23453
1993	21882
1994	22086
1995	22696
1996	22716
1997	23168
1998	23519
1999	23800
2000	24414
2001	24418
2002	23652
2003	23653
2004	23684
2005	25343
2006	25172
2007	25172
2008	25380
2009	25662
2010	25661
2011	28095
2012	28095
2013	28094.34
2014	29441
2015	27432.44
2016	27448.94