FORT LAUDERDALE - More than 51,000 undocumented Cubans entered the United States last year - a dramatic surge over 2014.

Newly released immigration numbers for the final three months of 2015 show that 17,071 Cubans arrived in the U.S. without prior authorization, bringing the calendar year total to 51,011, according to figures from the U.S. Customs and Border Protection.

That is an 84 percent increase over 2014.

"The numbers are going up and are going up fast," said Sebastian Arcos, associate director of the Cuban Research Institute at Florida International University.

The 2015 count does not include more than 20,000 Cubans given official permission annually by the U.S. to immigrate, or those who overstay tourist visas.

Since President Barack Obama announced the renewal of diplomatic relations with Cuba in December 2014, more and more Cubans have decamped for the United States. Many have cited a bleak Cuban economy and said they feared the U.S. would soon revoke their special status, which generally allows them to stay, with benefits, once they arrive in the U.S.