*! version 2.1.0  9/8/94        sg30: STB-23
* Edward Whitehouse  Institute for Fiscal Studies
pr def lorenz
  version 3.1
  local varlist "req ex max(1)"
  local if "opt"
  local in "opt"
  local options "B2title(string) L1title(string) OFfset TItle(string) YLAbel(string) XLAbel(string) *"
  local weight "fweight"
  parse "`*'" 
  confirm new var _share _perc _sort _use
  if "`l1title'" == "" {local l1title "cumulative proportion of `1'"}
  if "`b2title'" == "" {local b2title "cumulative proportion of sample"}
  if "`title'"=="" { local title "        Lorenz curve"}
  if "`offset'"=="" { local axis "noaxis xline(0,1) yline(0,1)" }
  if "`ylabel'"=="" { local ylabel "ylab(0,.25,.5,.75,1)" }
    else if "`ylabel'"=="." {local ylabel}
    else local ylabel "ylabel(`ylabel')"
  if "`xlabel'"=="" { local xlabel "xlab(0,.25,.5,.75,1)" }
    else if "`xlabel'"=="." {local xlabel}
    else local xlabel "xlabel(`xlabel')"
  quietly { 
    gen byte _use=1 `if' `in'
    gen _sort = -`varlist' if _use==1
    sort _sort
    su `varlist' [`weight'`exp'] if _use==1
    local wt : word 2 of `exp'
    if "`wt'"=="" {gen _share = sum(`varlist'/(_result(1)*_result(3))) if _use==1
                   gen _perc = [_n]/_result(1) if _use==1}
    if "`wt'"~="" {gen _share = sum(`varlist'*`wt'/(_result(1)*_result(3))) if _use==1
                   gen _perc = sum(`wt'/_result(1)) if _use==1}
    gr _perc _share _share if _use==1, b2ti("`b2title'") ti("`title'") l1ti("`l1title'") c(ll) s(ii) `xlabel' `ylabel' `axis' `options'
    drop _perc _share _use _sort
  end