OTC pain pills are a ~4 billion dollar industry. There are 320 million people so that's ~1$ / month in pain pill per person. And that's including both stuff that goes bad and is never used and daily Aspirin taken for cardiac health. https://www.chpa.org/OTCsCategory.aspx
5% of the population does take daily pain medication. At the same time it's common to go months without taking anything for pain.
"There was about 300 million pain prescriptions written in 2015,"
https://www.cnbc.com/2016/04/27/americans-consume-almost-all...
While 2017 numbers are not in. 2016 Prescription pain medications are down 6% from 2015 and down 18% from 2012. https://www.cdc.gov/drugoverdose/maps/rxrate-maps.html
And again, we are talking less than one prescription per year per person on average. With many of these prescriptions for 2-3 days worth of pain management. Though again, a minority of people get a lot of pain medication.
That article is borderline irresponsible with how it reports that metric.
80% of global prescription opiate medications are filled in the US, but that doesn't mean that 80% of those prescriptions are consumed in the US (or consumed at all). Nor does it include no-prescription opiates, which are generally much easier to obtain in most countries around the world (and also a lot cheaper) than their prescription counterparts.