sysuse sp500, clear 
gen month = month(date)
sort month
by month: egen lo = min(volume)
by month: egen hi = max(volume)
format lo hi %10.0gc
by month: keep if _n==_N
#delimit ;

twoway rcap lo hi month, 
  xlabel(1 "J"  2 "F"  3 "M"  4 "A"  5 "M"  6 "J" 
                 7 "J"  8 "A"  9 "S" 10 "O" 11 "N" 12 "D")
  xtitle("Month of 2001")
  ytitle("High and Low Volume")
  yaxis(1 2) ylabel(12321 "12,321 (mean)", axis(2) angle(0))
  ytitle("", axis(2))
  yline(12321, lstyle(foreground))
  msize(*2)
  title("Volume of the S&P 500", margin(b+2.5))
  note("Source:  Yahoo!Finance and Commodity Systems Inc.")
;
#delimit cr