First, pardon me if I'm demonstrating a fundamental ignorance of battery electrics. That is very likely!
I'm very aware that the max storage capacity of Leaf batts degrades over time and use.
However, I'm wondering if the efficiency of charging stays roughly the same, or worsens, over the life of the battery. To be more specific, say 10kwh is used from my home source for a charge. Will this provide me about the same driving distance when the batt is new AND when the batt is old? In other words, if 10kwh is put INTO the batt, will I always be getting the same energy BACK OUT of the batt, as long as the batt still has fair capacity? If not, then I suppose there would be a somewhat growing inefficiency with the life of the batt, and per-mile cost of operation would grow.
I'm particularly interested in how this has worked in the older 24kwh batts, since they have likely experienced the most degradation. Are drivers still getting a mileage-per-kwh similar to what they got out of the same batt in 2011?