diff --git a/doc/configuration.txt b/doc/configuration.txt
index b78eaf8e9..6a0511067 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -21470,7 +21470,7 @@ Please refer to the table below for currently defined variables :
   |   | %ID  | unique-id                                     | string      |
   |   | %ST  | status_code                                   | numeric     |
   |   | %T   | gmt_date_time                                 | date        |
-  |   | %Ta  | Active time of the request (from TR to end)   | numeric     |
+  | H | %Ta  | Active time of the request (from TR to end)   | numeric     |
   |   | %Tc  | Tc                                            | numeric     |
   |   | %Td  | Td = Tt - (Tq + Tw + Tc + Tr)                 | numeric     |
   |   | %Tl  | local_date_time                               | date        |