Pretty much what it says on the tin:
It's the beginning of 2016. Due to a fast-spreading virus, humans have lost the ability to reproduce themselves. The virus makes current artifical fertilization techniques useless as well. As a result, the population starts decreasing, due to the complete lack of newborns.
Now, how much time would be needed to have a 10% decrease of the population, assuming 7 billion people living on Earth before the crisis?
A bit of backstory on the question
I wrote a story which started with this premise and tried - without much success - to figure out how much time would have humans to "react" and actively find a cure before the population drop becomes so severe that:
- strategic facilities (like power plants, food production chains...) starts being abandoned due to lack of personnel;
- only medical laboratories are mantained active in order to try to find a cure, while the rest of the research is stopped or diverted to solve the problem.
Since if I had asked this, it would have been probably too broad/opinion based (correct me if not), I have resorted to the question in italics, in order to reduce the scope.
I hope the question is both answerable and on topic. If not, feel free to point it out.