+Export the number of values (a C<DERIVE>) falling within the given range. Both,
+I<lower_bound> and I<upper_bound> may be a fractional number, such as B<0.5>.
+Each B<Bucket> option specifies an interval C<(I<lower_bound>,
+I<upper_bound>]>, i.e. the range I<excludes> the lower bound and I<includes>
+the upper bound. I<lower_bound> and I<upper_bound> may be zero, meaning no
+lower/upper bound.
+
+To export the entire (0–inf) range without overlap, use the upper bound of the
+previous range as the lower bound of the following range. In other words, use
+the following schema:
+
+ Bucket 0 1
+ Bucket 1 2
+ Bucket 2 5
+ Bucket 5 10
+ Bucket 10 20
+ Bucket 20 50
+ Bucket 50 0
+
+Metrics are reported with the I<type> C<bucket> and the I<type instance>
+C<E<lt>TypeE<gt>[-E<lt>InstanceE<gt>]-E<lt>lower_boundE<gt>_E<lt>upper_boundE<gt>>.
+
+This option may be repeated to calculate more than one rate.
+
+=back
+
+=back