Exoplanet numbers are growing, albeit slowly

BBC : Although Earth-based astronomers have observed about 1000 exoplanets so far and the Kepler space telescope has detected thousands more potential candidates, there could be as many as 17 billion in the Milky Way galaxy. Exoplanets are planets that lie outside the solar system; astronomers have determined that among the known exoplanets, as many as 12 could be habitable—meaning that water could exist as a liquid on their surface. At present, exoplanets can only be detected indirectly, either by the amount of light they block when passing in front of their sun or by their gravitational pull on their sun as they orbit. Many more are waiting to be discovered and cataloged, according to Abel Mendez of the University of Puerto Rico. The only thing holding astronomers back is the lack of funding and available space telescopes.