Original: Since the belt was discovered in 1992, the number of known Kuiper belt objects (KBOs) has increased to over a thousand, and more than 70,000 KBOs over 100 k in diameter are believed to exist.
Simplified: After the Kuiper belt was discovered in 1992, the number of known Kuiper belt objects (KBOs) has added to over a thousand, and more than 70,000 KBOs over 100 km (62 mi) in diameter.