A record 1,335 people were listed as renouncing their U.S. citizenship or long-term residency in the latest quarterly disclosure from the Treasury Department, released on Thursday.

The total is the highest quarterly number of expatriates since a law requiring the publication of their names was enacted in the 1990s, according to Andrew Mitchel, a lawyer in Centerbrook, Conn., who tallies the lists of names. The previous quarterly record was 1,130 for the second quarter of 2013, he says.

The new figure puts 2015 on pace to exceed the total of 3,415 renunciations in 2014, which was itself a record. That was up 14% from 2,999 individuals in 2013, the previous record.

Experts link the growing number of renunciations by citizens and permanent residents to a tax enforcement campaign against U.S. taxpayers with undeclared offshore accounts. The campaign began after Swiss banking giant UBS admitted in 2009 that it had encouraged U.S. taxpayers to hide assets in secret Swiss accounts.

But the campaign has made the financial lives of more than seven million Americans living abroad more difficult, because the U.S. taxes nonresident citizens on income earned anywhere in the world, and U.S. tax liabilities can apply to the children born to Americans abroad. In many cases, there are only partial offsets available for double taxation.