Commercial air travel last year dropped to its lowest level since the government began keeping statistics, according to a new report issued by the Department of Transportation.

The report indicates that airlines operated 40% fewer flights during the entirety of the year than they had in 2019, as the coronavirus pandemic paralyzed several sectors of the economy.

Airlines operated 4.7 million flights in 2020 compared to 7.9 million flights the prior year – a difference of some 3.2 million flights and the lowest number since the department began tracking the metric in 1987.

The agency’s data indicates that the number of flights operated in the U.S. was on the decline in early 2020, falling from more than 673,000 in December 2019 to 583,000 in March 2020. The number of flights operated in April 2020 dropped precipitously, as pandemic lockdowns went into effect: The Transportation Department reported 194,000 flights operated that month, a decline of more than 66%.

The department’s data indicates that airlines canceled 6% of their scheduled domestic flights in 2020 – more than three times the 1.9% of flights canceled in 2019, reflecting the general volatility of travel as consumers remained wary of booking flights months into the pandemic.