An exoplanet is a planet that orbits a star other than the Sun. Exoplanets are also called extrasolar planets. Since 1988, more than 3000 exoplanets have been found. As of May 2016, there are 3406 planets in 2550 planetary systems. This includes 577 multiple planetary systems.
The Kepler space telescope, launched in 2009 has discovered more than 2000 exoplanets. The HARPS which was launched in 2004 has found over one hundred exoplanets. Kepler has also stumbled upon a few thousand candidate planets but it is possible that about 11% of those can be false alarms. On an average, a star has at least one planet with about 1% of them having more than one planet. The largest discovery of exoplanets on a single day is 1284 when Kepler discovered them on 10th May, 2016.