I ran across an older blog post that I think is very relevant given the Target breach as so any people will be setting up new ATM pin numbers to secure their ATM cards.
The most popular password is 1234 with nearly 11% of the 3.4 million passwords are 1234 !!!
I knew that 1234 would be popular but 11% is just a really high percentage of people using this PIN number. When taking the top 20 most popular PIN numbers in this sample set a little over 25% of the populations PIN numbers are used. That’s the top 20 most popular PIN numbers out of the total possible 10,000 PIN numbers which are available when using a 4 digit PIN which is what basically all banks use.
The blog post is a little geeky on the math and statistics side of things, but it makes for some interesting reading.