You just have to figure it out. You need to know what a prime number is first, then you can calculate it. A prime is a number that is divisible only by itself and one, or has factors of one and itself, only.
So, if a number is divisible by any number other than 1, or itself, it is not prime.
First, I thought that 2009 might be the next prime year - so I tested it. I got up to 2009/7 and found out that 2009 is NOT a prime year. I'm sure that 2010 is not prime, so I'll test 2011 next. So, what I do is use a calculator and see if it's divisible by 2, 3, 4, 5, 6, 7, ...... and so one until I figure out whether it is a prime or not. Maybe there is a simpler method for doing this, but if that is the case, I don't recall the method right now. You test 2011 yourself to see if you think it is prime. If you discover that it is, there is your answer. If not, move on to another year. I can bet you that 2012 is not a prime year, simply because it ends in an even number. But, maybe 2013 is prime. You try it out and see what you come up with.
I have a BS in math and am a teacher.