fix period select problem

diff --git a/stat2.py b/stat2.py
index 80f4d58..7a68a3e 100755 (executable)
--- a/stat2.py
+++ b/stat2.py
@@ -54,6 +54,8 @@ class StatApp(BigBlack):
         if start_month == 1:
             start_month = 12
             start_year -= 1
+        else:
+            start_month -= 1
         end_year = start_year
         end_month = start_month + 1
         if end_month > 12: