Percentage of dry land surface with sea level elevation lower than 1 km Being this my first questions on this .SE I hope that the topic is appropriate.

I've been told that 99% of the living species on earth live in between -200m and 800m above sea level, this made me just wonder how much of earth surface lies in this elevation span, but I couldn't find the answer googling. 

1) Does anybody have a source to check what percentage of dry land has sea level elevation lower than 1 km (or 800m, or in between -200m and 800m...)?

2) How should I interpret the information given to me about the number of living species? I would just say for the 99% of the living species the intersection between the "natural habitat" and the altitude "-200m - 800m" is non empty, is it correct? Is there a source where I can check this information?

Thanks in advance!!
(Fig. 2.4 of Deep-Sea Biology: A Natural History of Organisms at the Deep-Sea Floor)

8.3% of the Earth's surface is above 1 kilometer.

This corresponds to about 29% of the land area.

So 71% of the land area is below 1 km.