diff --git a/misc/munin/wormhole_transit_bytes b/misc/munin/wormhole_transit_bytes
index 0b765ce..39cc404 100755
--- a/misc/munin/wormhole_transit_bytes
+++ b/misc/munin/wormhole_transit_bytes
@@ -33,5 +33,5 @@ if time.time() > updated + 5*MINUTE:
     sys.exit(1) # expired
 
 value = db.execute("SELECT SUM(`total_bytes`) FROM `usage` WHERE `started` > ?",
-                   (rebooted,)).fetchone()[0]
+                   (rebooted,)).fetchone()[0] or 0
 print("bytes.value", value)
diff --git a/misc/munin/wormhole_transit_bytes_alltime b/misc/munin/wormhole_transit_bytes_alltime
index 290042d..380ac07 100755
--- a/misc/munin/wormhole_transit_bytes_alltime
+++ b/misc/munin/wormhole_transit_bytes_alltime
@@ -32,5 +32,5 @@ updated = db.execute("SELECT `updated` FROM `current`").fetchone()[0]
 if time.time() > updated + 5*MINUTE:
     sys.exit(1) # expired
 
-value = db.execute("SELECT SUM(`total_bytes`) FROM `usage`").fetchone()[0]
+value = db.execute("SELECT SUM(`total_bytes`) FROM `usage`").fetchone()[0] or 0
 print("bytes.value", value)