diff --git a/app/controllers/report_controller.rb b/app/controllers/report_controller.rb
--- a/app/controllers/report_controller.rb
+++ b/app/controllers/report_controller.rb
@@ -118,6 +118,7 @@
       d = (DateTime.now.in_time_zone - sub.submitted_at) / 24 / 60 / 60
       @histogram[:data][d.to_i] += 1 if d < range
 
+      next unless sub.points
       @summary[:count] += 1
       user[sub.user_id] = [user[sub.user_id], (sub.points >= @problem.full_score) ? 1 : 0].max