The first two digits of 580 1/ are the production year and month codes, and 58 indicates the production of 20 12 and 10/0. Batch numbers 580 1, 5806 and 5804 all represent the products produced in October12 and 10. By analogy, 60 was produced in February of 20 12, and 630 1 was produced in March of 20 13.