How wide is the spine of this album--3 inches, 4 inches?? I had an answer of 3 inches, but how could it fit all those protector pages as advertised? I have a 4-inch binder with 46 plastic protector pages, each with 2 12 x 12 papers (for a total of 92 pages of paper and 46 plastic pages. And it is full!! Thank you again!