Standard&Poor's Ratings Services has assigned its 'AA+' long-term rating to Portsmouth, N.H.'s series 2012 general obligation (GO) bonds and affirmed its 'AA+' long-term rating and underlying rating (SPUR) on the city's existing GO debt. The outlook is stable. The 'AA+' ratings reflect the city's: Location and participation in, and access to, large regional employment centers; Diverse property tax base, with extremely strong per capita market value and strong household income level; Very strong financial position, with strong management practices and policies; and Low-to-moderate debt burden. The city's full faith and credit GO pledge secures the bonds. Officials will use bond proceeds to refund a portion of the city's GO bonds dated Sept. 15, 2002, and to finance wastewater