In 2012, Chicago’s mass transit system saw its largest growth in 22 years, the Chicago Transit Authority announced on Wednesday.

The CTA said that ridership grew to 545.6 million rides last year, an increase of 2.4 percent from 2011, according to a statement from CTA.

Rail ridership was at its highest level in 50 years, increasing to 231.1 million rides in 2012, according to the CTA.

Bus ridership was also up, increasing to 314.4 million rides, an increase of 4.05 million rides from 2011.

Mayor Rahm Emanuel used the announcement as an opportunity to tout infrastructure investments that have been made under his administration.

“Public transportation plays a vital economic role in the Chicago region, and this historic growth reflects the need for continued investments across the system,” he said in a statement.

“As we continue to heavily invest in the transit system as a whole, these trends will continue, creating jobs throughout Chicago and improving the prospects of Chicagoans from every neighborhood,” the mayor said.

The mayor’s office also pointed out that ridership “has seen some of its sharpest increases during the tenure of Mayor Emanuel.”

“The CTA has more than $4 billion in projects under way or planned that will improve safety, enhance the customer experience and boost overall reliability of the bus and rail system – and we’re doing this while providing 1.7 million rides each weekday,” said CTA president Forrest Claypool.