For Boston area commuters, the MBTA’s Green Line has long been a source of frustration.

A 2016 post on the Thrillist Boston website ranked the Green Line last among the MBTA lines, writing, “The city’s oldest subway line is also its most maddening.”

New data released this month confirms that despite state efforts to improve the performance of the MBTA, the Green Line is still a problem.

The Massachusetts Department of Transportation, in its fiscal 2018 scorecard, found that the Green Line remains the least reliable of the MBTA routes.

The report measures reliability by looking at the percent of customers who wait no longer than the amount of scheduled time between trains.

The Green Line was considered reliable just 77.6 percent of the time, an improvement of 1.1 percent over the previous year. In contrast, the Red, Blue and Orange lines were each ranked as reliable more than 90 percent of the time.

The Silver Line, which operates a bus rather than a train, was reliable 79.3 percent of the time.

The Green Line is the only light rail line, which means it has to cross intersections and operate in traffic. According to the metrics, Green Line trains traveled, on average, 8,240 miles before having a mechanical failure that took the train out of service.

On the heavy rail lines, where stations are farther apart and generally underground, cars went between 45,000 miles (on the Red and Orange lines) and 80,000 miles (on the Blue line) before a mechanical failure.

The MBTA announced last week that it had put the first of 24 new Green Line cars into service. The new cars are expected to improve the line’s reliability.