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Saddam has a smart solution, but it carries some weaknesses. Imagine a source named 'Fresno, CA' (with comma in the string). split_part() would be fooled by the separator character in the string ...

To avoid such corner case problems and preserve original data types, use a (well-defined!) row type instead. You can create a composite type permanently with CREATE TYPE or register a temporary one with CREATE TEMP TABLE:

CREATE TEMP TABLE defso (def numeric, so varchar);  -- once per session!

SELECT country_code
     , country_name
     , (d14).def AS deflator_2014  -- note the parentheses!
     , (d14).so  AS source_2014
     , (d15).def AS deflator_2015
     , (d15).so  AS source_2015
     , (d16).def AS deflator_2016
     , (d16).so  AS source_2016
FROM   crosstab (
    'SELECT country_code, country_name, year, (deflator, source)::defso
     FROM   deflator
     ORDER  BY 1'
  , 'SELECT generate_series(2014, 2016)::int2'
   ) AS ct (country_code int2
          , country_name text
          , d14 defso
          , d15 defso
          , d16 defso
   );

I also removed the unnecessary CTE and simplified a bit.

While dealing with only a hand full of years, you can do without crosstab() and use self-joins:

SELECT country_code, country_name
     , d14.deflator AS deflator_2014
     , d14.source   AS source_2014
     , d15.deflator AS deflator_2015
     , d15.source   AS source_2015
     , d16.deflator AS deflator_2016
     , d16.source   AS source_2016
FROM        (SELECT * FROM deflator WHERE year = int2 '2014') d14
FULL   JOIN (SELECT * FROM deflator WHERE year = int2 '2015') d15 USING (country_code, country_name)
FULL   JOIN (SELECT * FROM deflator WHERE year = int2 '2016') d16 USING (country_code, country_name)
ORDER  BY country_code;

Using FULL [OUTER] JOIN since we can't assume a row for every combination of (country_code, year). This way we get the same result as with the crosstab query above.

Including country_name in the join condition seems redundant, but if we don't, we have to use COALESCE(d14.country_name, d15.country_name, d16.country_name) AS country_name to defend against missing rows. This functionally dependent value shouldn't be in the table to begin with. Should be in a country table in a properly normalized schema.