Approximating Art Consumption

My friend asked today how much audience are we expecting for our collaborative artistic installation. We translated the question into "how much of the American population would be interested in our project?". Our guess started from the total population, around 300 million. Consider the 100 million population between the oldest and youngest 100 million. Our project has to do with both music and sculpture. Let's say about one out of 10 adults go to artist events (galleries, shows, etc.). That's 10 million. Of that 10 million show-goers, if one out of 10 people like our project, that's 1 million people! Unfortunately I'm not sure how optimistic or pessimistic we're being here.