diff --git a/goal_tools/gerrit.py b/goal_tools/gerrit.py
index 9b3922c..72f0bdd 100644
--- a/goal_tools/gerrit.py
+++ b/goal_tools/gerrit.py
@@ -121,28 +121,33 @@ class Review:
 
     @property
     def reviewers(self):
-        for label in self._data['labels']['Code-Review']['all']:
-            if label['value'] not in (2, -1):
-                # Only report reviewers with negative reviews or
-                # approvals to avoid counting anyone who is just
-                # leaving lots of +1 votes without actually providing
-                # feedback.
-                continue
-            yield Participant(
-                'reviewer',
-                label['name'],
-                label['email'],
-                _to_datetime(label['date']),
-            )
-        for label in self._data['labels']['Workflow']['all']:
-            if label.get('value', 0) != 1:
-                continue
-            yield Participant(
-                'approver',
-                label['name'],
-                label['email'],
-                _to_datetime(label['date']),
-            )
+        labels = self._data['labels']
+
+        if 'Code-Review' in labels:
+            for label in labels['Code-Review']['all']:
+                if label['value'] not in (2, -1):
+                    # Only report reviewers with negative reviews or
+                    # approvals to avoid counting anyone who is just
+                    # leaving lots of +1 votes without actually providing
+                    # feedback.
+                    continue
+                yield Participant(
+                    'reviewer',
+                    label['name'],
+                    label['email'],
+                    _to_datetime(label['date']),
+                )
+
+        if 'Workflow' in labels:
+            for label in labels['Workflow']['all']:
+                if label.get('value', 0) != 1:
+                    continue
+                yield Participant(
+                    'approver',
+                    label['name'],
+                    label['email'],
+                    _to_datetime(label['date']),
+                )
 
 
 def cache_review(review_id, data, cache):