diff --git a/docs/yap.tex b/docs/yap.tex
index ffe5e193f..db7c435c6 100644
--- a/docs/yap.tex
+++ b/docs/yap.tex
@@ -5045,13 +5045,22 @@ Defines the relation: @var{K} is a currently defined database key whose
 name is the atom @var{A}. It can be used to generate all the keys for
 the internal data-base.
 
-@item key_statistics(+@var{K},-@var{Entries},-@var{Size})
-@findex key_properties/3
-@snindex key_properties/3
-@cnindex key_properties/3
+@item key_statistics(+@var{K},-@var{Entries},-@var{Size},-@var{IndexSize})
+@findex key_statistics/4
+@snindex key_statistics/4
+@cnindex key_statistics/4
 Returns several statistics for a key @var{K}. Currently, it says how
-many entries we have for that key, @var{Entries}, and what is the
-total size spent on the key, @var{Size}.
+many entries we have for that key, @var{Entries}, what is the
+total size spent on entries, @var{Size}, and what is the amount of
+space spent in indices.
+
+@item key_statistics(+@var{K},-@var{Entries},-@var{TotalSize})
+@findex key_statistics/3
+@snindex key_statistics/3
+@cnindex key_statistics/3
+Returns several statistics for a key @var{K}. Currently, it says how
+many entries we have for that key, @var{Entries}, what is the
+total size spent on this key.
 
 @item get_value(+@var{A},-@var{V})
 @findex get_value/2
diff --git a/pl/utils.yap b/pl/utils.yap
index 2850ecb5d..41149c1d7 100644
--- a/pl/utils.yap
+++ b/pl/utils.yap
@@ -478,7 +478,11 @@ statistics(stack_shifts,[NOfHO,NOfSO,NOfTO]) :-
 	'$inform_stack_overflows'(NOfSO,_),
 	'$inform_trail_overflows'(NOfTO,_).
 
+key_statistics(Key, NOfEntries, TotalSize) :-
+	key_statistics(Key, NOfEntries, ClSize, IndxSize),
+	TotalSize is ClSize+IndxSize.
 
+	
 %%% The unknown predicate,
 %	informs about what the user wants to be done when
 %	there are no clauses for a certain predicate */