(Toronto) Canada’s rental housing shortage could quadruple to 120,000 units by 2026 unless it gets a serious boost, the Royal Bank estimated Wednesday in a new report.

Canada will need to add 332,000 rental units over the next three years—a 20% increase from the 70,000 units built last year—to reach the optimal vacancy rate of 3%.

Canada’s rental housing stock grew by 2.4% in 2022. Growth was 7.4% in Calgary, 5.5% in Ottawa-Gatineau, and 2.1% and 1.4% in Toronto and Montreal, respectively.

According to the Royal Bank, slow growth in Canada’s two most populous cities is being overtaken by rapidly growing demand, in part due to high levels of immigration.

The vacancy rate in Canada fell in 2022 to its lowest level in 21 years, at 1.9%.

Competition for housing also led to the largest annual increase in rent growth on record, at 5.6% for a two-bedroom unit.