Besides, no one holds a big announcement to announce Catholics who switch to other Christian denominations. It happens all the time.
Not as often as you think. Andrew Greeley did a study that showed most disaffected Catholics actually becoming areligioius,not joining another sect or faith. Anecdotally I see this with my family and friends. Many have left the structure of the Church. Some have ceased any belief. None have sought out another way or faith.