diff --git a/api/api_v1/endpoints/query.py b/api/api_v1/endpoints/query.py
index 83fe2b2..aaec520 100644
--- a/api/api_v1/endpoints/query.py
+++ b/api/api_v1/endpoints/query.py
@@ -621,7 +621,7 @@ async def retention_model(request: Request,
             max_v = int(df[g_data['columnName']].max())
             min_v = int(df[g_data['columnName']].min())
             interval = (max_v - min_v) // 10 or 1
-            for i in range(min_v, max_v, interval):
+            for i in range(min_v, max_v+1, interval):
                 zidai.append([i, i + interval])
             true_group.append(zidai)