diff --git a/restic_exporter/restic_exporter.py b/restic_exporter/restic_exporter.py
index e5aa1f8..ef551f2 100644
--- a/restic_exporter/restic_exporter.py
+++ b/restic_exporter/restic_exporter.py
@@ -51,7 +51,8 @@ class restic_exporter:
             'tree_blobs',
             'data_added',
             'total_files_processed',
-            'total_bytes_processed'
+            'total_bytes_processed',
+            'total_duration'
         ]
         print(f"# HELP {self.metric_name} {self.metric_description}.")
         print(f"# TYPE {self.metric_name} counter")