With a firm knowledge and proven experience in the oil and gas industry, StargasVenture may consider a gas swap contract calling for the exchange of 1 m3 of gas at the end of each year for a period of 3 years. The discount factors for maturities of 1, 2 and 3 years are 0.96, 0.92 and 0.87. In most cases, gas storage is costly; the proportional storage costs equal 1% per year with annual compounding. Meanwhile, there is no convenience yield on gas, and the current spot price is $1.75 per m3. In this case, which party in the swap transaction is more exposed to credit risk over the life of the swap, a seller or a buyer? Please carefully answer the question and show your reasonings.