When exactly was the Ceramic Sea Dweller 4000 116600 first sold in the market place?

[Stratton]

I have just been offered a Ceramic Sea Dweller 4000 that the seller says dates from 2011. I rang Rolex London who told me the Ceramic SD 4000 was introduced in 2008. I have been out of touch with all things Rolex for a while, but I thought, probably wrongly, that the Ceramic SD 4000 was a more recent model than 2011. So, when exactly was the 116600 introduced? Thanks in advance for any replies.