function interp_lc_lim_group. In case of succes will replace interp_lc_lim
generalization for n countries from a region for example
still not "nice", some for there and there
same results than two-sex interp_lc_lim when n=2 and each sex in each group
not decided if argument must be id or group
function
interp_lc_lim_group. In case of succes will replaceinterp_lc_limgeneralization for n countries from a region for example still not "nice", someforthere and there same results than two-sexinterp_lc_limwhen n=2 and each sex in each group not decided if argument must beidorgroup