Once
Every 4 (four)years.
1-2 in a 1,000 children are born with this each year
About twice a year.
once a year
several times a year
Cleft lip and cleft palate are very common and occur in about 1 or 2 of every 1,000 babies born in the United States each year
About twice a year.
about 1 year tops
every 4 years
TWICE!!
It is very very rare that they will occur maybe 12 tornadoes a year
On average, 1