increase (something) by (something)
To expand something to a certain extent. Our aggressive new marketing campaign has increased our small company by 25 percent in the past year. What was once a tiny local choir club has increased by leaps and bounds over the years, becoming one of the state's largest organized choir communities.
increase something by something
to enlarge something by an amount or degree. They increased the size of the house by two hundred square feet. The engine size on the new model has been increased by a small amount.