It happened in 2016, 2018, 2020, 2022, 2025 and 2026, so 6 out of last 11 years. Not sure if I would count it as too rare.
Corrections (down 10% or more): about one per year on average. The Nasdaq is more volatile than the S&P 500, which has a correction closer to every 1.5 to 2 years.
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That's every other year, which is quite different from 2+yearly, which is exactly the point the gp was making.