The S&P 500 hit it's high of 2,941 on September 21st. As I write this, three months later on December 21st, the index has touched 2,435 for a decline of 17%. The 2015-16 bear market lasted just about nine months and declined 15%. Very mild for a bear market (so mild in fact, that many don't even count it as a bear).
I'm sticking with my prediction that this bear will be shorter - and steeper - than the last one.