There are a few reasons why we don't list the amount of tickets sold:

• The movie business never started reporting tickets sold. From the inception, it's always been raw dollars, so the data for tickets sold literally does not exist for older movies.
• Not all tickets are equal. An evening ticket is more expensive than an afternoon ticket, and IMAX ticket or 3D ticket is more expensive than a standard ticket, a ticket at a big city mall multiplex is more expensive than a ticket at a family-owned drive-in theater in the country, etc. So just listing the raw ticket amounts wouldn't tell you how much was made.
• The studios don't really care about tickets sold, they care about profit.