CW vs SSB: How do they compare?

We know that CW gets through better than SSB under noisy or weak signal conditions but how much better is it? 

Here's a test where I used a web SDR to compare by signal while switching between modes and power levels. The SDR was about 700km away. I did the test on 7 MHz under poor band conditions during the middle of the day. 

PS: I've now written six books on various aspects of amateur radio. Whether you experiment with antennas, enjoy QRP or are starting out in radio there's a book for you. Find out more here.