diff --git a/planetstack/monitor/monitordriver.py b/planetstack/monitor/monitordriver.py
index 77e8bfd..50e208c 100644
--- a/planetstack/monitor/monitordriver.py
+++ b/planetstack/monitor/monitordriver.py
@@ -7,6 +7,7 @@
         self['average'] = 0
         self['sum'] = 0
         self['unit'] = 'units'
+        self['stat_list']=[]
         # stat_list is a list of dicts
         # [ {'timestamp': datetime, 'value': value} ]