Silence fell upon the room during a tai chi class at the Senior Center on Wednesday.

More than a dozen senior citizens moved gracefully across the floor with their hands forming fists and legs extended.

Tai chi is one of many classes experiencing a gradual increase in attendance as the baby-boomer population has continued to age.

The Senior Center, 28 S. Linn St., has almost doubled its number of younger members from 2006 to 2012, and the aging baby boomer population is one of the main reasons.

“We’ve known baby boomers are coming of age, and we’re providing services for that,” said Linda Kopping, a Senior Center coordinator. “People retire at 65, and it used to be that after that. people didn’t have long to live. Now, there’s a new period where people may be living for another 20 or 30 years. It’s important to maintain a healthy and active lifestyle and we help provide that.”

According to the Corporation for National and Community Service, the baby boomers make up 28 percent of the U.S. population. The oldest baby boomers turned 65 in 2011 and can expect to live to 83, on average.

The average age of members at the Senior Center has drastically dropped over the last five years. In 2006, 29 percent of members were in their 60s. In 2012, that percentage increased to more than 38. In the past year, the total number of members at the center has increased by 500 people. As of January, the membership totaled 1,604, compared to 922 in 2006.

As the number of class participants increases, so does the number of classes. Mary Dusterhoft, a volunteer tai-chi teacher since 2000, said she’s noticed a dramatic change.

“When I first started out, if you had two people in your class, you felt fortunate,” the 71-year-old said. “There has been a big influx of people over the years. Now, an average class is around 19-20 people for the [intermediate] class.”

Members of the intermediate class did not include any baby boomers — people born between 1946 and 1964, but the older senior citizens said they have noticed a younger crowd of members within the past few years.

“There has been a large number of people in their 50s and early years,” said 70-year-old member Ed Rolenc. “We have been seeing a lot more here; this place has quite the reputation.”

Rolenc, also on the program committee for the center, said an increase in the number of academic classes such as math and science is helping the members improve their minds as well as their bodies.

One of the major changes the center has done to appeal to the younger demographic is to improve the weight room as well as offer more classes, such as tango dancing. Michelle Buhman, a program specialist, said in the next few years, she expects the younger demographic to continue to rise.

Buhman said the classrooms had to be reorganized to hold more people at a time, and more classes have been added. She said that while this is a positive increase, it does have its drawbacks.

“It’s actually been a real challenge to me,” she said. “We don’t want to turn anyone away, but the [volunteer teachers] only want to teach a class so many times. We’re running out of space in so many rooms. The [increase in attendance] has really taken off in the past few years.”