As you’ve probably heard, attendance at the Taste of Chicago dropped about 10 percent from last year, or 300,000 visitors—a big drop, but not as bad as the difference between 2009 and 2010, when attendance dropped by 700,000. It’s now down to 2.3 million, not quite 1.5 million off its mid-2000s peaks.

All the reasons cited in the Trib and Sun-Times postmortems seem to make sense in aggregate—no fireworks, no big-name musical acts, reports of flash mobs, and, of course, the economy. That last one interested me the most, since living in a food city and all, what people are spending on food and when is of some interest to me.

It turns out the Taste was preceded by a substantial drop in the Restaurant Performance Index, as small-biz reporter Sarah Needleman* wrote in the Wall Street Journal. The RPI had been recovering from months of bad news for the restaurant industry, climbing above 100, the magic number that indicates expansion. And in May, things took a turn for the worse, and portend more:

Even so, restaurant operators are not as optimistic about the future. The index’s measurement of restaurant operators’ six-month outlook in four areas — same-store sales, employees, capital expenditures and business conditions — stood at 100.6 in May, down from a level of 101.5 in April. Further, just 41% of operators said they expect to have higher sales in six months, down from 55% in January. Twenty percent expect their sales volume in six months to be lower, up from a mere 8% in January.

In other words, the RPI measures not just current restaurant economic health, but also restaurant owners’ perceptions of business in the near future. The decline is bad news, since, as Calculated Risk (the reason I follow the RPI) points out, restaurants were out of the hole that started in 2007, and were hovering around an econo-culinary Mendoza Line since last year.

Obviously the Taste was a more subdued affair this year, so that can’t be discounted. But despite its status as a special event, it’s also basically a big, temporary restaurant. So it’s hard not to think that it would respond to the economy in similar ways as the restaurant industry as a whole.

* Related: "For Small Businesses, Recession Isn’t Over"

Photograph: Chicago Tribune