US energy firms added oil rigs for a 16th week in a row, extending a drilling recovery into a 12th month even as the pace of those additions has slowed in recent weeks as crude prices have held below $50 a barrel.

Drillers added six oil rigs in the week to May 5, bringing the total count up to 703, the most since April 2015, energy services firm Baker Hughes reported on Friday.

While that is more than double the same week a year ago when there were only 328 active oil rigs, the pace of those additions has declined over the past four weeks to the lowest since the week to March 10, according to Reuters.

Despite recent price declines, analysts continued to project US energy firms would boost spending on drilling and pump more oil and natural gas from shale fields in coming years with energy prices expected to climb in future months.

US crude output averaged 9.3 million barrels per day in the week ended April 28, its highest since August 2015, according to federal energy data.