The rating on Portage, Mich.'s bonds reflects: Strong economic performance, Solid financial operations, and Moderately low debt levels. Mitigating factors include some tax base concentration and limited revenue-raising flexibility. Portage is located halfway between Chicago and Detroit on Interstate 94 in Kalamazoo County. The city covers 34.5 square miles and has a population of 44,360. Portage has a large commercial and industrial base that represents two-thirds of taxable value and includes the leading employers Pharmacia Corp. (formerly Upjohn), Summit Polymers, and Stryker Corp. The city is a net importer of jobs, with a labor force of 25,600 and very low unemployment of 1.6% in 2000. Wealth levels are above average at 120% of the nation's median household income level, while