President Donald Trump said Monday at the White House he wanted to top off the National Petroleum Reserves after oil futures plunged to historic lows.

“We are looking to put as much as 75 million barrels into the reserves themselves,” Trump said. “That would top it out, that would be the first time in a long time that has been topped out.”

West Texas Intermediate crude oil for May delivery fell to negative $37.63 per barrel on Monday, with other contracts trading to just above $20 a barrel.

The president joked with a Bloomberg reporter during the White House press briefing about knowing the price of oil, despite catching the same reporter off guard in a previous briefing.

“I bet you know the price of oil right now, don’t you,” Trump said.

“I do,” the reporter replied, “Do you know the price of oil?”

“I do,” Trump said. “I actually do.”

The reporter then said that oil was minus 37 dollars.

“No one’s ever heard of negative oil before,” Trump marveled. “But it’s for a short term.”

The president would need Congress to approve spending to top off the oil reserves.

The Republican effort to pass more spending for the national oil reserves was dropped in the massive March stimulus spending bill, as Democrats demanded similar spending funds for windmills and solar energy.