What is a hipster? Look at this fucking hipster...

I'm watching that uni challenge now, but I don;t get why i got a question wrong:

3rd of March 2009 was a square root day as 03/03/09, when was the last square root day before it?

I thought 01/01/01, but the answer was 09/09/81. Why am I wrong?

Square Root Day occurs on the following dates each century:

• 1/1/01
  
• 2/2/04
  
• 3/3/09
  
• 4/4/16
  
• 5/5/25
  
• 6/6/36
  
• 7/7/49
  
• 8/8/64
  
• 9/9/81