Vital rates

Vital rates refer to how fast vital statistics change in a population. There are 2 categories within vital rates: crude rates and refined rates.
Crude rates measure vital statistics in a general population.
Refined rates measure the change in vital statistics in a specific demographic.

Marriage rates

The national marriage rates since 1972,in the US have fallen by almost 50% at six people per 1000. According to Iran Index and National Organization for Civil Registration of Iran Iranian divorce rate is in the red at its record highest level since 1979, divorce quotas were introduced to curb enthuitasim.