Citing rising costs to provide its services, Comcast is raising rates on its cable video customers by an average of about 3.5 percent, according to a letter sent to Mayor Karl Dean this week.

Although cable television rates will rise, Comcast will not issue an increase to cable internet or digital voice customers.

Comcast customers will be made aware of the increase in a letter soon to be mailed out. The letter states that costs associated with new programming, particularly for sports, have gone up. Comcast spends $6 billion a year on programming, according to the letter.

“While we are highly focused on controlling our costs for the benefit of our customers, price adjustments are a necessity in view of the increased cost of doing business in this challenging economic environment, including gas prices, healthcare costs, increases in the cost we pay for programming, and technology and service improvements,” Comcast Director of Government Affairs Terri Weldon said in a statement.

“Even with these pressures, our average customer will pay only about 3.5 percent more next year, well under the rate of inflation.”