Without immigration, the U.S. population will shrink starting in 2033 in part “because fertility rates are projected to remain too low for a generation to replace itself,” the Congressional Budget Office said.

The reduced projections from last year were the results of a decline in projected fertility rates over 30 years from 1.70 births per woman to 1.60 births per woman and less immigration because of an executive order last June that temporarily suspends asylum processing at the border when U.S. officials deem they are overwhelmed, the budget office said. Replacement happens at a rate of 2.1 births per woman.