Bloomberg reports that Canada’s border chief said the U.S. border is unlikely to be completely reopened until 75% of Canadians are fully vaccinated.

The world’s longest undefended border has been closed to most travel since March 2020. On Friday, Canada extended the restrictions until at least July 21, though it’s expected to announce the easing of some rules Monday for fully vaccinated citizens.

“We haven’t reached the finish line, and the finish line is when a significant majority of Canadians, approximately 75%, are fully vaccinated,” Public Safety Minister Bill Blair told. At present, less than a fifth of Canadians have received two shots, according to data compiled by CTV News.

Airlines, tour operators and other businesses on both sides of the border have been pleading for a reopening, with the vital summer season about to begin, and Canada’s go-slow approach is causing frustration. Blair’s announcement Friday that Canada would extend the border restrictions was met with some unusually blunt language from Brian Higgins, a New York Democrat who represents a border district.

Canada prioritized giving first doses to as many people as possible before moving on to second doses amid a shortage in vaccine supplies. As a result, some 66% of Canadians have received one shot, but only 18% have had two, according to data compiled by CTV News. In contrast, about 45% of Americans have had two doses, according to the Bloomberg Vaccine Tracker.