Stata绘图直方图彼此相邻

Question

我想绘制一个直方图，显示按法官的出生队列从每个法学院毕业的法官人数。

我正在使用：

twoway (histogram j_lawschool_num if j_cohort_num == 1 | j_cohort_num == 2, color(red%30)) ///        
       (histogram j_lawschool_num if j_cohort_num == 3 | j_cohort_num == 4, color(green%30)), ///   
       legend(order(1 "Judges Born Before 1959" 2 "Judges After 1959" )) xlabel(1/6,valuelabel alternate) ///
       xtitle(Law School Category) ytitle(Density) graphregion(color(white) margin(large)) bgcolor(white)

但这些条形图彼此重叠。如何使它们彼此相邻，以使同一法学院类别中的酒吧不重叠？

当前看起来像：