Unemployment is divided into two problems: long-run unemployment and short-run unemployment. The natural rate of unemployment is the rate of unemployment that is normally experienced. It is not necessarily a desirable rate of unemployment and it changes due to changes in policy and in the economy. This is the long-run rate of unemployment around which an economy"s unemployment rate fluctuates. Cyclical unemployment occurs when unemployment deviates from its natural rate. The bureau of labor statistics publishes employment data every month. This data is based on the current population survey of roughly 60,000 households. The unemployment rate is the percentage of the labor force that is unemployed. It can be calculated using the following formula: Unemployment rate = (number of unemployed/labor force) x100. Unemployment rates are also calculated for specific demographic characteristics such as age, sex and race. The labor-force participation rate is the percent of adults participating in the labor force. Labor-force participation rate = (labor force/adult population) x100.