Show the outcome code of mailshots along with the number of mailshots in each outcome code.
SELECT outcome_code ,  count(*) FROM mailshot_customers GROUP BY outcome_code
SELECT outcome_code ,  count(*) FROM mailshot_customers GROUP BY outcome_code
[{'outcome_code': 'No Response', 'count(*)': 5}, {'outcome_code': 'Order', 'count(*)': 10}]