The duration of recessions follows an exponential not a power law

Ormerod and Mounfield (Physica A 293 (2001) 573) analyse GDP data of 17 leading capitalist economies from 1870 to 1994 and conclude that the frequency of the duration of recessions is consistent with a power law. But in fact the data is consistent with an exponential (Boltzmann–Gibbs) law.