Apology for Calendar 2014: October 20th was missing!

I have to apology for my mistake in the 2014 Calendar.  Just before I have received an email from one of my friends about missing the 20th October.

Having checked in my file of 2014 Calendar, indeed, the 20th was missing; the 21st came straight after 19th.  Although I had checked through the calendar when writing the numbers, I couldn't find the mistake before finishing the work.  It mustn't have happened, and mustn't be repeated!

I will endeavour to avoid any mistake.  (There is no missing number in my 2015 calendar.  I am relieved.)