New York (CNN Business) The boom-to-bust oil market has rapidly gone from spiking to crashing.

US oil prices declined nearly 1% and briefly broke below $60 a barrel on Friday, tumbling deeper into a bear market.

Crude closed lower for the 10th day in a row. That's the longest losing streak since July 1984, according to S&P Platts.

In barely a month, crude has plunged 21% -- and that's since closing at a four-year high of $76.41 on October 3.

Friday's low of $59.28 a barrel is the weakest price since February.