It depends on what you take to be the beginning and what the end. It lasted two years if you understand it as from the time it was revealed to the time Nixon resigned. It lasted 5 years if you take it from the time Nixon began doing it to the time he resigned.
The Song Dynasty was first civilization in the world to use banknotes, aka paper money. They also were the first to use gunpowder, and the first to make a permanent navy. They were also the first to discern the North using a true compass. They had many, many firsts, which helped develop the world into how it is today.
Sorry, that this is only one half of your answer. But, I hope this still helps.
Answer:
Grocery shortages have ranged from reasonably concerning to harmlessly annoying this year. For example, the surge in panic-buying caused shortages of meat and flour in the spring, which understandably scared many Americans. But there have also been shortages of our favorite beverages and snacks, not necessarily the things we can't live without, but rather the things we don't want to live without, as food companies had to trim down their production pipelines.
