Before revision: +Half-month lettersLetterDatesAJanuary 1–15BJanuary 16–31CFebruary 1–15DFebruary 16–29EMarch 1–15FMarch 16–31GApril 1–15HApril 16–30LetterDatesJMay 1–15KMay 16–31LJune 1–15MJune 16–30NJuly 1–15OJuly 16–31PAugust 1–15QAugust 16–31LetterDatesRSeptember 1–15SSeptember 16–30TOctober 1–15UOctober 16–31VNovember 1–15WNovember 16–30XDecember 1–15YDecember 16– 31 Reference
After revision: +Half-month lettersLetterDatesAJanuary 1–15BJanuary 16–31CFebruary 1–15DFebruary 16–29EMarch 1–15FMarch 16–31GApril 1–15HApril 16–30LetterDatesJMay 1–15KMay 16–31LJune 1–15MJune 16–30NJuly 1–15OJuly 16–31PAugust 1–15QAugust 16–31LetterDatesRSeptember 1–15SSeptember 16–30TOctober 1–15UOctober 16–31VNovember 1–15WNovember 16–30XDecember 1–15YDecember 16– 31 3Table