Same-store sales at U.S. retail chain stores fell 0.2% last week after a 1% decline the week before, according to the index published Tuesday by the International Council of Shopping Centers. Sales growth year-over-year improved to 3.7% from 3.5% the week earlier. "This past week, sales results were somewhat mixed," said Michael Niemira, ICSC's chief economist. "Though the last two weeks we have seen sales pull back a bit, overall sales continue to be holding up and are relatively healthy." ICSC expects May same-store sales to rise 3% to 3.5%