diff --git a/Documentation/iostats.txt b/Documentation/iostats.txt
index c76c21d..65f694f 100644
--- a/Documentation/iostats.txt
+++ b/Documentation/iostats.txt
@@ -71,6 +71,8 @@
     measured from __make_request() to end_that_request_last()).
 Field  5 -- # of writes completed
     This is the total number of writes completed successfully.
+Field  6 -- # of writes merged
+    See the description of field 2.
 Field  7 -- # of sectors written
     This is the total number of sectors written successfully.
 Field  8 -- # of milliseconds spent writing