egen group = group(code year)
gen median = .
count
local n "r(N)"
sort group

quietly forvalues i = 1/`r(N)' {
gen temp = da if `i' != _n
by group: egen temp2 = median(temp)
replace median = temp2 in `i'
drop temp temp2
}

replace median = . if group == .

clist if group == 1, noobs