It's not uncommon but not the norm either. Majority of people are still looking to retire as soon as they can afford it without stepping down their comfort. Some love their job so much and don't know what else to do that they continue but it's really an exception in my opinion.

Also there have been proof that the earlier you retire the longer your life expectancy is. Thus it might be biased as richer can afforded earlier retirement, better food and have access to better treatment (depending on the country) to help them having more chances to live older.