IMPOSSIBLE TRIVIA Holdover Question: Number of People With it in Common Has Tripled in Past 100 Years?

This week on Lite Rock Impossible Trivia, I'm giving you concert tickets to see Seal perform in Ovation Hall at Atlantic City's brand new Revel Casino on Friday, July 20th.

This morning's question was held over from yesterday... The number of people who have this in common has tripled over the past 100 years.  Researchers say it may have something to do with older women having babies.  What is it?

The answer?  When I gave the hint that, "on one hand you once had 3% of people with this in common and, on the other hand, you now had 11% of people who do", Kate from Northfield knew it was...left-handed people!