Item 7A. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

Interest rate risk can be quantified by measuring the financial impact of a near-term adverse increase in short-term interest rates on variable-rate debt outstanding. Our total long-term debt consists of both fixed and variable interest rate facilities. Our senior notes have fixed interest rates ranging from 2.40% to 3.85%. These fixed-rate facilities reduce the impact of changes to market interest rates on future interest expense. Our senior revolving line of credit has variable interest rates, which are based on the Prime Rate, the Federal Funds Rate, or LIBOR, depending upon the specific type of borrowing, plus any applicable margins. We currently have interest rate swap agreements which effectively convert our $250 million of 2.40% fixed-rate senior notes due March 2019 and our $350 million of 3.30% fixed-rate senior notes due August 2022 to variable rates. The applicable interest rates under these swap agreements are based on LIBOR plus an established margin. Our earnings would be affected by changes in these short-term variable interest rates. At our current level of borrowing, a one-percentage-point increase in our applicable rate would reduce annual pretax earnings by $9.1 million.

Although we conduct business in foreign countries, international operations are not material to our consolidated financial position, results of operations, or cash flows. Additionally, foreign currency transaction gains and losses were not material to our results of operations for the year ended December 31, 2018. Accordingly, we are not currently subject to material foreign currency exchange rate risks from the effects that exchange rate movements of foreign currencies would have on our future costs or on future cash flows we would receive from our foreign investment. To date, we have not entered into any foreign currency forward exchange contracts or other derivative financial instruments to hedge the effects of adverse fluctuations in foreign currency exchange rates.

The price and availability of diesel fuel are subject to fluctuations due to changes in the level of global oil production, seasonality, weather, and other market factors. Historically, we have been able to recover a majority of fuel-price increases from our customers in the form of fuel surcharges. We cannot predict the extent to which volatile fluctuations in fuel prices will continue in the future or the extent to which fuel surcharges could be collected to offset fuel-price increases. As of December 31, 2018, we had no derivative financial instruments to reduce our exposure to fuel-price fluctuations.