To date, nearly 4,000 exoplanets have been discovered and considered "confirmed." However, there are nearly 3,000 other "candidate" exoplanet detections that require further observations in order to say for sure whether or not the exoplanet is real.
Remarkably, the first exoplanets were just discovered about two decades ago. We live in an extraordinary time where in the span of a single generation, the centuries-old question "Are there planets orbiting other stars?" has been answered with a resounding "Yes!"
Since the first exoplanets were discovered in the early 1990s, the number of known exoplanets has doubled approximately every 27 months.