The IBM 503, the last valve computer, that Cobol and Fortran, the first languages were developed on, had 20 bit words.

So an 80 column card could fit 4 words across. Thats why teletypes and terminals had 80 coulmns of text - so they were the same size as punch cards.

Fortran only used 72 columns, so the last 8 were unused.

It seems weird, but on early computers bytes were not based on multiples of 8 or 4 (like 8 but, 16 bit, 32 bit etc). Some computers had 15, 10, 7, 25, even 50 bit words.