Fix-up intro paragraph for collections docs.
diff --git a/Doc/library/collections.rst b/Doc/library/collections.rst
index f32ad76..ab9d505 100644
--- a/Doc/library/collections.rst
+++ b/Doc/library/collections.rst
@@ -16,30 +16,30 @@
__name__ = '<doctest>'
This module implements high-performance container datatypes. Currently,
-there are two datatypes, :class:`deque` and :class:`defaultdict`, and
-one datatype factory function, :func:`namedtuple`.
-
-.. versionchanged:: 2.5
- Added :class:`defaultdict`.
-
-.. versionchanged:: 2.6
- Added :func:`namedtuple`.
+there are three datatypes, :class:`Counter`, :class:`deque` and
+:class:`defaultdict`, and one datatype factory function, :func:`namedtuple`.
The specialized containers provided in this module provide alternatives
to Python's general purpose built-in containers, :class:`dict`,
:class:`list`, :class:`set`, and :class:`tuple`.
-Besides the containers provided here, the optional :mod:`bsddb`
-module offers the ability to create in-memory or file based ordered
-dictionaries with string keys using the :meth:`bsddb.btopen` method.
+.. versionchanged:: 2.4
+ Added :class:`deque`.
+
+.. versionchanged:: 2.5
+ Added :class:`defaultdict`.
+
+.. versionchanged:: 2.6
+ Added :func:`namedtuple` and added abstract base classes.
+
+.. versionchanged:: 2.7
+ Added :class:`Counter`.
In addition to containers, the collections module provides some ABCs
(abstract base classes) that can be used to test whether a class
-provides a particular interface, for example, is it hashable or
+provides a particular interface, for example, whether it is hashable or
a mapping.
-.. versionchanged:: 2.6
- Added abstract base classes.
ABCs - abstract base classes
----------------------------