LONDON (AP) — Energy producer BP says first quarter earnings fell 9% amid lower oil prices.

The London-based company says underlying replacement cost profit — the industry’s preferred measure of performance because it strips out one-time items and changes in inventory values— fell to $2.36 billion from $2.59 billion in the same period last year. Net income rose 19% to $2.93 billion.

Brent crude, the benchmark for international oil, hit an 18-month low in December and averaged $63.13 a barrel in the first quarter, down 5.5 percent on the year, before picking up more recently.

BP says it cut carbon emissions from operations by 1.7 million tons in 2018. Earlier this year, BP responded to shareholder pressure by announcing that executive compensation would be partly determined by progress in meeting carbon reduction targets.