Cost of clothing leaps up with back-to-school surge.(American Express survey)(Brief Article)

Back to school.

Add to that phrase the wore "sale" and you've got a retailer's delight.

According to this year's American Express Retail Index, released last month parents and teenagers nationwide will spend an average of $548 on back-to-school shopping this year, a 20 percent increase over 1999. Back-to-school budgets are at their highest level since American Express introduced the Retail Index in 1995.

The survey, conducted by telephone in June and July 2000, interviewed 1,000 randomly selected adults (equal numbers of men and women), to create a national sample. A separate telephone teen survey interviewed 500 boys and girls, ages 1217. The survey looked at consumer back-to-school spending, buying attitudes, shopping trends and preferences, with regional breakouts.

Increased spending by …