As of 2-4 years ago, the number of programmers working in the industry was doubling every 5 years. That might not seem relevant until you realize that it means half of all programmers have less than 5 years experience. If you have 10 years in the industry, you're more senior than 75% of your co-workers.

That's why anyone with 5 years on the job is considered "senior", even though most in most professions you're just getting out of the entry level after 5 years.