Settle down?

[edinapole]

Can you guys explain me the meaning of this sentence please? (I came across it in gamepro.com):
The PS3 launch tittle list settled down over the last couple of months.
_ I don't know what exactly "settle down" mean in this statement and if possible, please tell me what the whole senctense mean.... Thanks

[mykwyner]

When the game was first released to the public (launch) they were introducing new programs for it (titles) at a very high rate (maybe five or six per week). Now that the game has been available for a while, the rate of introduction of new programs for it has decreased (settled down) to maybe two or three per month.

I made those numbers up for illustrative purposes. I have no idea how many games or programs are sold.