diff --git a/bower.json b/bower.json
index c7973be..cc4be41 100644
--- a/bower.json
+++ b/bower.json
@@ -1,6 +1,6 @@
 {
   "name": "nvd3",
-  "version": "1.1.14-beta",
+  "version": "1.1.15-beta",
   "homepage": "http://www.nvd3.org",
   "authors": [
     "Bob Monteverde",
@@ -18,7 +18,7 @@
   ],
   "license": "Apache License, v2.0",
   "dependencies": {
-    "d3": "~3.3.5"
+    "d3": "~3.3.13"
   },
   "ignore" : [
     "**/.*",
diff --git a/nv.d3.js b/nv.d3.js
index 8e9f671..5d9adae 100644
--- a/nv.d3.js
+++ b/nv.d3.js
@@ -3231,7 +3231,11 @@ nv.models.cumulativeLineChart = function() {
       if (!line.values) {
          return line;
       }
-      var v = lines.y()(line.values[idx], idx);
+      var indexValue = line.values[idx];
+      if (indexValue == null) {
+        return line;
+      }
+      var v = lines.y()(indexValue, idx);
 
       //TODO: implement check below, and disable series if series loses 100% or more cause divide by 0 issue
       if (v < -.95 && !noErrorCheck) {
diff --git a/src/models/cumulativeLineChart.js b/src/models/cumulativeLineChart.js
index 9273144..d2de8bb 100644
--- a/src/models/cumulativeLineChart.js
+++ b/src/models/cumulativeLineChart.js
@@ -740,7 +740,11 @@ nv.models.cumulativeLineChart = function() {
       if (!line.values) {
          return line;
       }
-      var v = lines.y()(line.values[idx], idx);
+      var indexValue = line.values[idx];
+      if (indexValue == null) {
+        return line;
+      }
+      var v = lines.y()(indexValue, idx);
 
       //TODO: implement check below, and disable series if series loses 100% or more cause divide by 0 issue
       if (v < -.95 && !noErrorCheck) {