Copyright for 1992 added
diff --git a/Include/stringobject.h b/Include/stringobject.h
index 27fb243..2fb386b 100644
--- a/Include/stringobject.h
+++ b/Include/stringobject.h
@@ -1,5 +1,5 @@
 /***********************************************************
-Copyright 1991 by Stichting Mathematisch Centrum, Amsterdam, The
+Copyright 1991, 1992 by Stichting Mathematisch Centrum, Amsterdam, The
 Netherlands.
 
                         All Rights Reserved