What % of unique users visited a page (1 or more times)?

I have a chat feature on my site, which some of my users LOVE, and some don’t use at all. I’d like to know how many of my users visited the chat page (% of total unique users, I guess).

For example: if I had 10 users on my site last month and 3 of them each visited chat 10 times, while 7 of them never went to chat at all, I want to know that 3 people used the chat page (not that that the /chat page had 30 entries).

How can I get that?