Favorable conditions existed for world economic growth during the 1980s and early 1990s. Yet real GDP growth rates for 76 out of 87 countries included in this study decreased during this time, relative to the 1968-80 period. The middle income countries experienced the greatest decline in growth rates, followed by the low income group. Theory and evidence suggest that an increase in the instability of the growth rate of the money supply, largest in the middle income countries and next largest in the low income nations, contributed to this decline.