Coupon clipping is on the rise, according to Nielsen.
In June, a Nielsen survey of 50,000 consumers found that nearly one-third used grocery coupons once a week or more.  In December 2007, just one-fourth of those surveyed were clipping coupons at that rate, the Pittsburgh Post-Gazette reported Thursday. 
According to a separate study by Scarborough Research, a joint partnership with Nielsen and Arbitron, Milwaukee residents reported the highest rates of coupon clipping — 40% of all city households use grocery coupons once a week or more. 
Rochester, NY ranked second, with 38% of …