It's a grim milestone for Oklahoma's economy.
Tax collections from oil and natural gas production sank to a 17-year low in April, totaling just under $21 million.
The receipts are based on production in February, when oil was selling for around $30 a barrel.
It's trading this week at closer to $45 a barrel.
Overall tax collections last month were just over $1 billion -- the lowest April total in four years and nearly 11 percent less than in April 2015.