Step 1 : Introduction to the question "what percentage of the world uses the metric system"
...The Earth has a population of 7.046 billion. 94.7% of the world uses the metric system by population, rather than 99%. However, there are other ways to represent percent of the world. To give /u/Wiltron the benefit of the doubt, I'll also calculate the percent of the world that uses metric units, using other metrics.