The U.S. oil rig count ended 2016 just below year-ago levels as drillers added rigs during the week of Dec. 26 as part of the biggest recovery since a global oil glut crushed the market over two years.

Drillers added two oil rigs in the week to Dec. 30, bringing the total count up to 525, the most since December 2015 and 11 shy of the 536 rigs seen at the end of 2015, Baker Hughes Inc. said on Dec. 30.

Since crude prices recovered from 13-year lows in February to about $50 per barrel (bbl) in May, drillers have added a total of 209 oil rigs in 28 of the past 31 weeks, fueled by prices climbing to near 17-month highs.

The Baker Hughes oil rig count plunged from a record 1,609 in October 2014 to a six-year low of 316 in May as U.S. crude collapsed from over $107/bbl in June 2014 to near $26/bbl in February 2016.

U.S. crude futures were trading at $53.60/bbl on Dec. 30, on its way to growth of more than 40% for the year, the largest annual percentage growth since 2009.

Futures for both calendar 2017 and 2018 were trading around $56/bbl.

Analysts said they expect U.S. energy firms to boost spending on drilling and pump more oil and natural gas from shale fields in coming years now that energy prices are projected to keep climbing.

The total oil and natural gas rig count ended 2016 at 658, down 6% from the 698 at the finish of 2015.