a) Statistics on freight cars are based on marked loading capacity of cars since 1997, resulting in the adjustment of grouping of cars. Data marked
(1^*) refer to cars with a loading capacity of 20 tons and less, data marked
(2^*) refer to cars with a loading capacity of 61 tons, and
(3^*) refer to cars with a loading capacity of 70 tons and over. The same as in the following years.