diff --git a/problem/views/oj.py b/problem/views/oj.py
index d360858..0241e41 100644
--- a/problem/views/oj.py
+++ b/problem/views/oj.py
@@ -178,4 +178,4 @@ class ProblemSolvedPeopleCount(APIView):
             rate = "%.2f" % ((total_count - accepted_count) / total_count * 100)
         else:
             rate = "0"
-        return self.success(f"{rate}%")
+        return self.success(rate)