One in five sunlike stars harbors an Earth-size world that orbits in a "habitable zone"

Yep, that is not a typo.  The National Geographic blog writes:

• astronomers estimate that 22 percent of sunlike stars may be orbited by small, rocky planets that reside within so-called habitable zones, where they receive Earth-like levels of sunlight.

The Kepler satellite was tasked with finding  "exoplanets," using the "transits," method of the parent star to detect the planets.

At the end of it's working life, Kepler, had stared at 150,000 stars  in the direction of the constellations Cygnus and Lyra.  Out of that group of possible candidates the astronomers studied 42,000 stars that are like our sun or slightly cooler and smaller.   The results suggest that there might well be a habitable planet within 12 light years and this planet is orbiting a sun that we could see with the naked eye!

Another thing to consider is that if we look at just the Milky Way and use the same 22% of sunlike stars containing Earth like planets, then you come up with an astronomical amount of planets and stars that resemble the Earth Sol - solar system. 

Check out the complete National Geographic article HERE