(a) What is the current composition of the SA National Defence Force (SANDF) in terms of the number of members of former (i) statutory and (ii) non-statutory forces, and (b) what ranks do the specified members hold, (c) what is the total number of retirements that are expected in the next five years, (d) what impact will the retirements have on institutional memory, (e) what is the breakdown of members who will retire in the next five years by rank, gender and former force affiliation and (f) what is the current race, gender, and rank breakdown of the SANDF in 2018?