What are the different card types, and how many transactions have been made with each?
SELECT T2.card_type_code ,  count(*) FROM Financial_transactions AS T1 JOIN Customers_cards AS T2 ON T1.card_id  =  T2.card_id GROUP BY T2.card_type_code
Farklı kart türleri nelerdir ve her biriyle kaç işlem yapıldı?