What healthcare problems are consuming the largest share of healthcare dollars? Researchers decided to answer that question.

In total, the researchers analyzed 5.9 billion unique insurance claims, 150.4 million ambulance rides, dental procedures, and emergency room visits, 1.5 billion days spent within inpatient or nursing home care, and 5.9 million drug prescriptions. And they just published their results in the Journal of the American Medical Association.

Researchers say that when neck and low back pain are combined with other musculoskeletal disorders, including joint and limb troubles, Americans are spending more for treatment than on any other ailment or condition.

Just how much does that add up to? According to data from 2016, an almost inconceivable $380 billion was spent on spinal issues and joint pain.

In all (individuals, public insurance, private insurance), $3.1 trillion was spent on healthcare in the United States in 2016. That comes out to $9,655 for every U.S. citizen, and roughly 17.9% of the U.S. GDP. For reference on just how high prices have skyrocketed, in 1996, healthcare costs only represented 13.3% of the GDP.

“The vast costs associated with healthcare represent one of the most important and contentious issues facing Americans today,” says Dr. Joseph Dieleman of the Institute for Health Metrics and Evaluation (IHME) at the University of Washington’s School of Medicine and lead author of the study, in a release. “Our study provides comprehensive estimates over a 20-year period that highlight how healthcare and prescription drugs are paid for, what they are spent on, and how such payments have changed over time.”

Of all 154 medical conditions included in this research, just lower back and neck pain alone accumulated the highest expenditures ($134.5 billion). After that, diabetes ($111.2 billion), ischemic heart disease ($89.3 billion), and falls ($87.4 billion) weren’t far behind in terms of costs.

Predictably, the majority of those costs were paid for by insurance providers, both public and private.  Regarding lower back and neck pain; $76.9 billion was paid for by private insurance, and $45.2 billion was paid for by public insurance. Still, that left $12.3 billion that had to come out of someone’s pockets.

Meanwhile, private insurers paid $73.3 billion for other musculoskeletal disorders, public insurers covered $46.9 billion in costs, and $9.7 billion was paid for by individuals out of pocket.

For diabetes, $55.4 billion was paid by public insurance, $49.1 billion by private, and $6.7 billion was paid out of pocket.

How about ischemic heart disease? In all, $48.2 billion was paid for by public insurers, $37.9 billion worth of costs were covered by private insurers, and $3.2 billion was paid by individuals.

Finally, falls tallied a hefty tab as well; $40.7 billion was paid for by public insurance, $34.8 billion was paid for by private insurance, and $11.9 billion was settled out of pocket.

Most of that public insurance spending (58.6%) covered bill accumulated by patients over the age of 65. After adjusting for population and age fluctuations, public insurance spending increased much faster than private insurance. The study’s authors attribute this observation to Medicaid expansions.