16-5  Quality of Transport Routes|16-5QualityofTransportRoutes|Item|1990|2000|2010|2014|2015||LengthofRailwaysinOperation(km)|53378|58655.9|66239.019|66989.216|120970.4|Double-TrackingLength(km)|13024|21407.9|29683.617|32545.762|64687.1|Proportion(%)|24.4|36.4974367454936|44.8128874010045|48.5835839607378|53.5|LengthofHighways(km)|1028348|1679848|4008229|4463913|4577296|ExpresswayandClassItoIVHighways(km)|741104|1315931|3304709|3900834|4046290|Proportion(%)|72.0674324255991|78.3363137617213|82.448108628524|87.3859772804712|88.4|LengthofNavigableInlandWaterways(km)|109192|119325|124241.78|126280.02|127001|StandardWaterways(km)|59575|61367|62290.22|65362.28|66257|Proportion(%)|54.5598578650451|51.4284517075215|50.1362907067172|51.7597954133995|52.2||a)Lengthofrailwaysinoperationreferstothatofnationalrailwaysbefore2015,andreferstorailwaysofallthecountrysince2015,soitisnot|comparablewithpreviousyears.