"The highest number used is 75. The letters B, I, N, G, O are pre-printed above the five vertical columns, with one letter appearing above each column. The center space is marked "free." The printed numbers on the card correspond to the following arrangement: 1 to 15 in the B column; 16 to 30 in the I column; 31 to 45 in the N column; 46 to 60 in the G column and 61 to 75 in the O column" - wikipedia
Sometimes wiki is wonderful, (though not usually).
Your point being what exactly, or is this just another "Let's see how long we can keep this going" thread? Not that it's important, just like to know what I'm tryin' to be a part of is all.