Metro Transit ridership on buses and trains continued to slide in 2021 owing to the COVID-19 pandemic, but officials said they were hopeful more riders will return this year as the omicron variant eases.

Ridership in 2021 declined 6.5% from the previous year, but the number of Metro Transit passengers has dropped by more than half since before the COVID outbreak. In 2019, some 78 million riders used Metro Transit service, a number that dropped to 38 million in 2020 and 36 million last year.

"COVID impacted transit service almost exactly two years ago," when riders disappeared and service cuts resulted, said John Harper, Metro Transit's manager of contracted transit services, at a Metropolitan Council Transportation Committee meeting Monday.

Local bus service and light rail proved to be the most popular transit modes last year, accounting for about 86% of ridership. Commuter and express bus service accounted for just 2% of ridership, and Northstar rail, which serves the northern suburbs, less than 1%.

"Express ridership is really where we took our biggest hit," said Eric Lind, Metro Transit's research and analytics manager.

Metro Transit experienced "robust" ridership among high school and college students and all-day, all-purpose trips in 2021, officials said. But the transportation system continues to be challenged by the unpredictability of COVID, a shortage of operators resulting in trips and schedules being pared, and unpredictable travel patterns by riders.

The pandemic, and the transition it prompted for many from working in the office to working at home, may have permanently changed traditional commuter service ferrying suburbanites to downtown Minneapolis and St. Paul during morning and afternoon peak hours.

While several major employers have jump-started their return-to-work plans as omicron recedes among Minnesotans, it's unclear when — not to mention if — commuter service will return. The city of Minneapolis switched to a hybrid workplace plan on Monday, and major private employers will likely follow suit in March and April.

The biggest ridership drops in 2021 were reported on Northstar, down 67%, and overall bus service, which declined by 12%.

Among the different kinds of bus service, express bus service declined by 62% while demand for bus rapid transit service was essentially flat. Orange Line bus rapid transit, linking downtown Minneapolis and Burnsville largely along Interstate 35W, began service in December.

Of all the types of public transportation offered in the Twin Cities, only three saw an increase in ridership in 2021: Metro Mobility, by 26%; the Green and Blue light-rail lines, 4%; and Transit Link, 3%. Metro Mobility is a shared-ride public transportation service for those unable to use regular buses due to a disability or health condition, and Transit Link is a shared-ride, curb-to-curb service.

The pervasive spread of the omicron variant not only affected the passengers taking transit but also the drivers and operators providing it.

Only last month, some 300 cases of COVID were reported at Metro Transit — the highest level since the pandemic began, according to General Manager Wes Kooistra. So far this month, only 15 employees have been affected by the virus.

COVID "took drivers off the street because they were sick themselves or caring for loved ones who were sick," Lind said.

Metro Transit is currently 33 operators below ideal staffing levels, part of the overall shortage of workers in the current economy. "We can't provide the service we want unless we have the full complement of operators," Lind said.