What is the average age when a child is able to identify all the letters of the alphabet?

At how many months or years of age is a child typically able to identify all 26 letters of the alphabet? I am not asking about reciting the alphabet or singing the ABC song. I mean the age when a child can say the name of a letter that’s shown to him/her, or can find & point to a letter when asked to do so (e.g., “Where’s the B?”).

Any thoughts from either personal experience or otherwise would be appreciated.