diff -r efd9c589177a -r c0b4a8b5a012 toolkit/javascript/d3/src/core/quantile.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/javascript/d3/src/core/quantile.js	Thu Apr 10 14:20:23 2014 +0200
@@ -0,0 +1,8 @@
+// R-7 per <http://en.wikipedia.org/wiki/Quantile>
+d3.quantile = function(values, p) {
+  var H = (values.length - 1) * p + 1,
+      h = Math.floor(H),
+      v = values[h - 1],
+      e = H - h;
+  return e ? v + e * (values[h] - v) : v;
+};