Since each round is timed, they're predictable every year. The first round for 2012 lasted just over 3 hours; the 2013 first round draft lasted about 3 hours, 30 minutes.
12 years
23 years. The First Punic War (264 to 241 BC)
15 years, but ended shortly after the first emperors death.
They have been round for hundreds of years
About 100 years.
12 years
The first crusade lasted for 3 years.
20 years
20 years
9 999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999million years
The Constitution lasted 8 years.
8 years
20 years
20 years
20 years
first of all long* and 8 years
20 years