effects in several locations and normal field declines. Between 2016 and 2015, production increases from major capital projects, base business, and shale and tight properties were largely offset by normal field declines, the Partitioned Zone shut-in, the impact of civil unrest in Nigeria and planned turnaround activity.

The net liquids component of international oil-equivalent production was 1.20 million barrels per day in 2017, down 1 percent from 2016 and down 3 percent from 2015. International net natural gas production of 5.1 billion cubic feet per day in 2017 was up 23 percent from 2016 and 28 percent from 2015.

Refer to the “Selected Operating Data” table, on page 39, for a three-year comparison of international production volumes.

U.S. Downstream

U.S. downstream operations earned $2.94 billion in 2017, compared with $1.31 billion in 2016. The increase was primarily due to a $1.16 billion benefit from U.S. tax reform, higher margins on refined product sales of $380 million, lower operating expenses of $160 million, and the absence of an asset impairment of $110 million. Partially offsetting this increase were lower gains on asset sales of $90 million and lower earnings from the 50 percent-owned Chevron Phillips Chemicals Company LLC of $70 million, primarily reflecting the impacts from Hurricane Harvey.

U.S. downstream operations earned $1.31 billion in 2016, compared with $3.18 billion in 2015. The decrease was due to lower margins on refined product sales of $1.45 billion, lower earnings from the 50 percent-owned Chevron Phillips Chemicals Company LLC of $400 million and an asset impairment of $110 million. Partially offsetting this decrease were lower operating expenses of $80 million and higher gains on asset sales of $110 million.

Refined product sales of 1.20 million barrels per day in 2017 were down 1 percent, primarily due to divestment of Hawaii refining and marketing assets in fourth quarter 2016. Sales volumes of refined products were 1.21 million barrels per day in 2016, a decrease of 1 percent from 2015, mainly reflecting lower sales of diesel. U.S. branded gasoline sales of 528,000 barrels per day in 2017 decreased 1 percent from 2016 and increased 1 percent from 2015.

Refer to the “Selected Operating Data” table on page 39 for a three-year comparison of sales volumes of gasoline and other refined products and refinery input volumes.

International Downstream

International downstream earned $2.28 billion in 2017, compared with $2.13 billion in 2016. The increase in earnings was primarily due to higher gains on asset sales of $360 million, partially offset by higher operating expenses of $140 million. Foreign currency effects had an unfavorable impact on earnings of $65 million between periods.

International downstream earned $2.13 billion in 2016, compared with $4.42 billion in 2015. The decrease in earnings was primarily due to the absence of a $1.6 billion gain from the sale of the company's interest in Caltex Australia Limited in 2015, partially offset by 2016 asset sales gains of $420 million. Lower margins on refined product sales of $1.14 billion also contributed to the decline. Partially offsetting these