Conde Naste says:

A fast growing number of vacationers are looking for something to write home about besides cathedral tours and boutique shopping. According to Virtuoso, a consortium of upscale travel agencies, almost half of its affluent travelers between 34 and 52 now ask for nature or outdoor components when booking a vacation.

Arizona Office of Tourism says:

In 1998 domestic overnight visitors were at 24.4 million spending $447 per person, accounting for $10.9 billion dollars spent in the state.