A period of 75 years is called a "septuagenary."
The odds are 91% that any given 12-year period will include three leap years. The other 9% of the time there are two leap years in a 12-year period. There are never four leap years in a 12-year period.
A period of 10 years is called a decade.
A period of 100 years is called a century.
Oh, dude, a period of 12 years is called a "dozen years." Just kidding, it's actually called a "dozenal." But let's be real, who actually goes around saying, "Oh yeah, back in the dozenal of 2009..." Sounds more like a math problem than a casual conversation, am I right?
A period of 100 years is called a century.
A period of ten years is a decade.
a 12 month period is called a fiscal year, there is also a natural year.
The period of 100 years is called a century. A period of 10 years is a decade, and 1000 years is a millennium.
About 12 of our years.
12 years.
A period of forty years is called a quadragennial.