diff --git a/notebooks/wp5/glacier_distribution.ipynb b/notebooks/wp5/glacier_distribution.ipynb
index d66c651..9dadc11 100644
--- a/notebooks/wp5/glacier_distribution.ipynb
+++ b/notebooks/wp5/glacier_distribution.ipynb
@@ -345,7 +345,7 @@
     "\n",
     "\n",
     "gdf[\"region\"] = gdf[\"RGIID\"].str[6:8].astype(int)\n",
-    "grouped = gdf[[\"year\", \"AREA\", \"region\"]].groupby(\"region\")\n",
+    "grouped = gdf[[\"year\", \"decimal_year\", \"AREA\", \"region\"]].groupby(\"region\")\n",
     "means = {\n",
     "    \"arithmetic\": grouped[\"year\"].mean(),\n",
     "    \"weighted\": grouped.apply(\n",