diff --git a/swh/web/assets/src/bundles/webapp/history-counters.js b/swh/web/assets/src/bundles/webapp/history-counters.js
--- a/swh/web/assets/src/bundles/webapp/history-counters.js
+++ b/swh/web/assets/src/bundles/webapp/history-counters.js
@@ -38,6 +38,11 @@
   width = width - margin.left - margin.right;
   height = height - margin.top - margin.bottom;
 
+  // Make sure data points are sorted, by x coordinate then y coordinate.
+  historyData.sort(function(a, b) {
+    return a[0] - b[0] !== 0 ? a[0] - b[0] : a[1] - b[1];
+  });
+
   const firstPoint = historyData[0];
   const lastPoint = historyData[historyData.length - 1];