Data on annual number of doctor visits for individuals age 65 and older from the US Medical Expenditure Panel Survey for 2003.
Data are analyzed in Cameron, A. C., and P. K. Trivedi. 2010. Microeconometrics Using Stata. Rev. ed. College Station, TX: Stata Press.
Additional information on finite mixture models for count data and a similar example are found in Deb, P., and P. K. Trivedi. 1997. Demand for medical care by the elderly: A finite mixture approach. Journal of Applied Econometrics 12: 313-336. https://doi.org/10.1002/(SICI)1099-1255(199705)12:3<313::AID-JAE440>3.0.CO;2-G.