Exhibit 99.1

Last Updated 4/29/2008

Pinnacle West Capital Corporation

Quarterly Consolidated Statistical Summary
Periods Ended March 31, 2008 and 2007

List of Contents

2008 First Quarter Summary

2008 by Quarter

2007 by Quarter

2006 by Quarter

2005 by Quarter

Quarters may not sum to totals due to rounding.

The definitions of terms used in this statistical summary are contained
in the “Glossary of Terms” on the Pinnacle West website at:
http://www.pinnaclewest.com/files/investors/2008Q1QuarStatsGloss.pdf

This statistical data may be graphed in various quarterly or annual comparisons
using the “Interactive Charts” tool on the Pinnacle West website at:
http://www.pinnaclewest.com/main/pnw/investors/financials/quarterly/landing.html