Answer:
WELL THERE ARE MANY DIFFERENT WAYS AND IT REALLY DEPENDS ON THE GUY. I WOULD LET THE GUY PROPOSE TO YOU. YOU CAN DISCRETELY MENTION IT BUT LET HIM DO THE HARD STUFF.
Well, in places like India, women marry men so it's pretty cool for a woman to propose to her man. In your case however, it'll be better if you just give him a 'bait' to follow. The reason why your boyfriend hasn't proposed yet may be because he's not ready yet. So, if you're not careful and you propose, then you may need broad shoulders- to cry on! He'll turn you down, and it'll be difficult for him to return to that aspect of your relationship. Most guys view that as 'pressure', so be careful about it.
And, yes you can propose to your boyfriend. But, no you shouldn't. You can both watch movies that have proposal stuff in them so his mind will be drawn to the subject. Otherwise, just wait patiently. Unless, you want to be daring...Maybe, you should take a risk.