Bookings for the Phoenix Convention Center over the next 10 years have jumped more than 50 percent in the past 12 months, and city officials are crediting the increase to the convention center's $600 million expansion program.

As of June 2003, Phoenix Civic Plaza had 65 conventions and 183,332 delegates confirmed between 2004 and 2014. But as of June 30, 2004, those numbers had jumped to 102 conventions and 301,007 delegates confirmed for the same time frame.

The positive impact of 37 additional conventions translates into a $170.7 million increase in direct expenditures, said Scott White, sales and marketing vice president of the Greater Phoenix Convention & Visitors Bureau.

For groups tentatively booking space in Phoenix, as of June 2003, the convention center had 82 conventions with 222,376 delegates holding space and reviewing contracts between 2005 and 2015. But as of June 2004, Civic Plaza has 122 tentative conventions with 489,095 delegates holding space and reviewing contracts.

The additional 40 conventions, if the groups book Phoenix, translate into $404.3 million in additional expenditures, according to White's newest annual review of definite and tentative bookings. He said the past fiscal year "is one of the best years we've had" since 1998.

"That's a direct result of what's going on downtown with the (convention center) expansion and the hotel (a new 1,000-room Sheraton planned for the corner of Third and Van Buren streets)," White said. "The past couple of years, the tentatives were slowing down for various reasons, but now they're picking back up again. They're saying, 'You're expanding and you have a hotel coming? We're excited.'"

Phoenix officials said the $600 million expansion and the new hotel have caught the attention of large groups. In the past, these groups have taken their conferences to other cities because downtown Phoenix had too few large hotels and its convention facilities were insufficient.