Switching from Monthly to Yearly actually works out cheaper! You get 2 months on us, so you actually only pay 10 months!
To switch from Monthly to Yearly payments, head to your Account Settings in the top right corner of your account.
Then select Billing and find the box titles Upgrade Your Subscription. Please take a moment to read the information in this box, then click Upgrade to see the updated costs.
If you have already paid for a Month, the rest of the month you're in will be applied as credit. This gets discounted right away from your total price. If you're happy with the amount, click Proceed To Checkout.
Note: Once you complete checkout, you will be charged immediately for this upgrade.
Then just complete the checkout procedure and you're all done and paid for the year!