A nice summary of recent exoplanet discoveries. It’s early days yet, but a preliminary estimate is that the percentage of stars that have Earth-like planets (i.e., rocky and in the habitable zones of their stars) is about 34%.
As this article points out, the current indirect methods of planet hunting will not get us all that far in characterizing these worlds as they are discovered. To look for oceans and atmospheres, the next step is either a new generation of space telescopes for followup observations, or developing clever new ways to pull more information out of existing resources. As we enter an age of austerity it seems pretty clear which way we will have to go!