the amount depends on block height and the output of a Mersenne Twister random number generator which is seeded by the hash of the previous block in the blockchain.

see also https://github.com/mrtexaznl/mediterraneancoin/blob/master-0.8/src/main.cpp at line 1146

see also http://www.mediterraneancoin.org/ in the "Features" section for more detail on how subsidy is scheduled:

Special reward system: random block rewards depending on block number:
block number   reward
1-100k    random 1-100 MediterraneanCoins reward
100k - 200k    1-200 MediterraneanCoins reward
200k - 300k    1-150 MediterraneanCoins reward
300k - 400k    1-100 MediterraneanCoins reward
400k - 500k    1-70 MediterraneanCoins reward
500k - 600k    1-40 MediterraneanCoins reward
> 600k    20 MediterraneanCoins reward (flat)
after that, subsidy halves in 1036k blocks (~1 year)


200 million total coins