Without Using a Calculator

Without using a calculator -

You are driving a bus from London to Milford Haven in Wales.
In London, 17 people get on the bus.
In Reading, six people get off the bus and nine people get on.
In Swindon, two people get off and four get on.
In Cardiff, 11 people get off and 16 people get on.
In Swansea, three people get off and five people get on.
In Carmarthen, six people get off and three get on.
You then arrive at Milford Haven.

What was the name of the bus driver?