Kiwis wallets are in for a "hammering" this month, with Statistics New Zealand warning that 180,000 New Zealanders will celebrate - or not celebrate - their day of birth.
And those who were born on September 30 may or may not be happy to know they share their 'special' day with about 14,000 other Kiwis.
"Peak birthday" period begins on Saturday and in the 13 days between September 19 and October 1 the 10 most popular birthdays will occur, Statistics New Zealand senior demographer Kim Dunstan said.
At the other end of the spectrum, the least common birthdays tend to be around fixed public holidays like Christmas Day, she said.
After February 29, the least common birthdays in New Zealand are between December 24 and 27, January 1 and 2, Waitangi Day and Anzac Day.