ROLLS 5000 series product line made just for RE systems. Just scroll down to the bottom of the page and you will see where the numbers came from.
The other 90% you are correct, and discharging only 20% DOD will only yield 500 to 1000 cycles. However as of today there is no known Lithium or NiMh that can do more than 1000 cycles with 3rd party verification. NiMh will never be able to compete economically with lead acid technology simply for the fact that nickel is a semi-precious metal. Lithium has some promise but economically they are not there as of yet.