What is the approximate bandwidth required to transmit a CW signal?

Explication

A CW signal is one carrier switched on and off, and the keying sidebands extend only a small distance either side of it, growing with keying speed and with abrupt keying edges. At normal sending speeds with proper shaping the occupied width is on the order of 100 to 200 Hz, conventionally quoted as about 150 Hz, far below the voice figures of 2.4 and 15 kHz offered as distractors.