'1 years'::interval to months?

I have a column defined as type 'INTERVAL'.  It always contains values
with an integral number of months.  For example:

orca_v0_1=# select duration from budget;
    duration
---------------
  1 year
  7 mons
  1 year 5 mons
(3 rows)

Is there a way to query this column such that is only return the
integral number of months?  In the example above, I would like to see
12, 7, 17 returned.

I've tried using 'extract', but the resulting query is rather... shall
we say, inelegent:

orca_v0_1=# select extract(YEARS FROM duration)*12 + extract(MONTHS FROM
duration) from budget;
  ?column?
----------
        12
         7
        17
(3 rows)

PS: Finally, just out of curiousity, is it possible to return the
"fractional" number of months for the situation that an interval is '4
months 2 days'::INTERVAL ?

--

-**-*-*---*-*---*-*---*-----*-*-----*---*-*---*-----*-----*-*-----*---
  Jon Lapham
  Extracta Moléculas Naturais, Rio de Janeiro, Brasil
  email: lapham@extracta.com.br      web: http://www.extracta.com.br/
***-*--*----*-------*------------*--------------------*---------------