reg  l(0/1).dl h year1996-year2015, robust
est store ols
xtreg l(0/1).dl h year1996-year2015, fe
est store fe
xtabond dl h year1996-year2015
est store dabond
esttab ols dabond fe, b(%6.3f) t(%6.2f) mtitle(ols dabond fe)