CHICAGO -- Cubs season-ticket holders received a letter Friday to inform them that prices were going up 16 percent for the 2008 season.

An Infield Club Box seat season ticket for prime dates increased from $67 to $80, while an Outfield Club Box seat and Infield Field Box seat rose from $56 to $66 each for prime dates. Season-ticket holders who prefer the bleachers now will pay $45 for prime dates, compared to $42.

After the Cubs' 66-96 season in 2006, they decided not to raise season-ticket prices for 2007. But they had to do so this year, said Crane Kenney, Tribune Co. legal counsel, who is the liaison between ownership and the team. The 16 percent hike is the average overall increase for all dates (prime, regular and value) compared to 2007 prices.

"Since we took that year off, we put more than $300 million into the team last year, and re-upping with [Carlos] Zambrano at the end of this year and re-signing [Kerry] Wood, we're into the $400 million range," Kenney said Friday. "We also upgraded the playing surface, we put a lot of money back into the team and the field and the facility, and we're making an appropriate adjustment with the tickets."

Zambrano signed a $91.5 million contract in August, while Wood signed a one-year, $4.2 million deal on Monday. The new playing surface and drainage system at Wrigley Field cost another $1.6 million.

The Cubs' 2007 payroll was $110 million, and Kenney said that will increase in 2008, but he wouldn't specify how much.

The Cubs, who drew a record 3,252,464 fans last season when they won the National League Central Division, are trying to find other ways to generate revenue, and are considering more advertising in the ballpark. Last year, Under Armour ads were on the outfield doors for the first time.

"We'll continue to push the envelope a little bit and respect the essence of Wrigley Field," Kenney said.

There is one thing Kenney said they will not change.

"We're not going to touch the ivy," he said of the vines covering the outfield walls.

Prices for single-game tickets will be announced in February 2008.