For a selected group of tractors, the increase of unit operating cost has been analysed in relation to the USD exchange rate and oil price on world markets in the years 2003–2009. The analysis is based on tractors of various level of output power and diesel oil prices in Poland. An additional factor is the fluctuations of the average USD and EUR exchange rates, indirectly influencing the oil price. The analysis has shown that diesel oil price growth directly affected the operating costs within the analyzed group of tractors. In the years 2003, 2004, and 2005 the unit operating costs were growing proportionally to the growth of diesel oil price. In the years 2006 and 2007 the operating costs decreased in spite of the diesel oil price increase.

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