This followed a decade of growth in median income and decline in low-income rates in most metropolitan areas in the 1980s. [...] The develop- ment of industrial parks, new suburbs, and transportation infrastructure outside of the original CMA boundary all contribute to increasing the size of a metropolitan area, and contribute to the evolution of income and low income in the region. [...] The LICO is differentiated by family size and size of area of residence, with the larger CMAs predominantly falling in the 500,000+ population category and the smaller CMAs in the 100,000 to 499,999 category. [...] In the 1980s, median income growth was low in some western CMAs, reflecting the economic boom experienced in that area in the late 1970s and the impact of the 1981/82 recession in these CMAs. [...] However, in some CMAs this growth spurt at the end of the decade did not offset the declines suffered in the first half of the 1990s, and median incomes fell in four CMAs over the 1990s (Toronto, Sudbury, Thunder Bay and Vancouver).