Why is the 90's the 20th century and not the 19th century?

Anyway, long story short; The 1st Century after the Birth of Christ (AD, the year of our lord) was the dates from 0–99. Then, the 2nd Century was from 100–199… So on and son. This means that the dating system in use attributes the years 1900–1999 as the “20th Century” because it is the 20th Century after Christ was born. read more

Because 0–99 was the first century so 2000–2099 is the 21st century. It’s all a bit confusing because this calendar wasn’t invented till the 5th century CE when the Pope of the day decided to switch from the Roman Calendar (that dated from the foundation of Rome) to the Christian era. read more

The 20th Century was the first in history in which world population at the end of the century exceeded the number of deaths from all causes that occurred during the century. In all previous centuries the number of deaths during the century largely exceeded the number of world inhabitants at its end. read more