use "http://fmwww.bc.edu/repec/bocode/k/k401.dta", clear
replace totemp = totemp / 10000

zoib prate mrate totemp age sole, oneinflate( mrate totemp age sole) robust

// effect on total proportion
mfx, predict(pr) at(mean sole = 0)

// effect on probability of having a proportion 1
mfx, predict(pr1) at(mean sole = 0)

// effect on proportion given proportion < 1
mfx, predict(prcond) at(mean sole = 0)