This empirical note employs fractional integration techniques with allowance for seasonality to infer the degree of persistence in US self-employment rate using monthly data from 2000:01 to 2014:05. The results indicate orders of integration in the range of [0.5,1] implying nonstationary, but mean-reverting behaviour.
A time series analysis of US entrepreneurship. Evidence from fractional integration
Luis A. Gil-Alaña
James E. Payne
Applied Economics Letters Vol. 22 Issue 7