Matt Cutts from google has hinted at longer domain registration being a determining factor in google search engine rankings.
So yes I do believe it does help increase search engine rankings to have a domain registered longer than 1 year.
It shows that the website plans to stay online for a long time and not just vanish overnight.
But I think domain registration length only has a little bit of an affect. What really would help is an older domain name and website that's been online for a few years at least.
I find that websites that are 10 years old or older rank better than new websites that are only a few years old.
I've seen websites rank better that are 10 years old with a yearly domain registration.
Then I've seen websites not ranking as good that are only a few years old with a 10 year registration.
Ranking a website can take time.