Probability of the Heroes

What are probabilities to get rare, epic and legend heroes from the tavern without using any cards and does the Tavern level affect it ?
So far I get 2-3 rare heroes every week and, 1-2 epic heroes a month. I play everyday and I have not yet seen a legend hero but somehow other users in the tournament already have them. Did they spend coins to get those or how did they get it ?

According to game info, higher level taverns have a greater chance of getting "better" heroes. So a level 20 tavern will have Epic heroes appear more often than a level 19 tavern.

I have refreshed an Epic from a level 12 tavern once. So it's still possible even with a low level tavern.

To have a chance at getting a Legendary hero, you can use an Epic Hero Refresh card. They currently cost 200 gold. Some say you can get them free by refreshing in taverns, but I have only heard this from an untrustworthy player. I have refreshed over 3,000 times in level 20 taverns since beta and have never gotten a Legendary.

You can also get heroes from purchase awards, such as Alan and Alistar. Check your Dailies tab under Purchase Reward section.

Actual rates/chance figures have not been published and are unlikely to be.