In this Wednesday, Jan. 16, 2013 file photo, a Glock representative explains features of the Glock 37 Gen 4 .45 caliber pistol at the 35th annual SHOT Show, in Las Vegas. AP American taxpayers pay roughly $12.8 million every day to cover the costs of gun-related deaths and injuries— and that is a conservative estimate, according to a new report released by Mother Jones on the cost of gun violence in America.

The true cost, however, is not fully known, partly because of the vast sum that's been spent by the NRA and other gun rights activists to shut down research related to firearms, and partly because of the sheer number of expenses incurred when someone is shot.

What is known is that taxpayers cover roughly 87% of these costs, which include, but are not limited to:

Medical treatment

"Maybe $5 million?" responded one woman when asked how much her gun wound had cost between hospital bills, physical therapy, trauma counseling, in-home care, wheelchairs, customized vans, and lost income. Many people also have long-term problems such as bowel issues, arthritis problems, and chronic pain that keeps them hooked on pain medication and returning to the hospital.

Legal fees

Legal proceedings for the Aurora movie theater killer reached $5.5 million before the trial even got underway this spring — calling 9,000 prospective jurors to try the sole suspect, James Eagan Holmes, proved expensive.

James Holmes and his defense attorney Daniel King (R) sit in court for an advisement hearing at the Arapahoe County Justice Center in Centennial, Colorado June 4, 2013. Andy Cross/Pool/Reuters

Long-term prison costs

Keeping individuals charged with a gun-related crime costs the government and taxpayers more than $5.2 billion annually. It is the largest direct expense incurred by gun violence, according to Mother Jones.

Long-term medical and disability expenses

Victims of gun violence often suffer injuries so severe that they require round-the-clock care for the rest of their lives — and survivors can often live much longer than expected. The kind of skilled nursing care needed for a victim who is paralyzed or brain damaged can cost "upwards of $1.7 million." If the victim is a Medicaid patient, taxpayers foot the bill.

Mental health care

Trauma from gun injuries and homicides account for $410 million annually in direct mental-health costs, according to Mother Jones. "But that sum would rise substantially if all gun victims and their families could afford to seek counseling."

Emergency services

A 5-mile ambulance ride for a single victim can cost upwards of $800. Combined with the fees of inumerable other emergency services, each gun injury requiring hospitalization costs about $583,000.

Police investigations

When even one person dies or is injured in a shooting, officers are required to respond and launch a full investigation into the attack. As Mother Jones notes, when a gunman opened fire at a shopping complex near Portland, Oregon in December 2012, "more than 150 officers from at least 13 local, state, and federal law enforcement agencies responded. The investigation that lasted more than three months and culminated in a report nearly 1,000 pages long." These lengthy investigations are largely paid for by taxpayers.

A police officer pulls up tape marking the perimeter around Ferguson Police Department in Ferguson, Missouri, March 12, 2015. REUTERS/Jim Young

Security enhancements

Tightening security at schools (hiring security guards, paying for metal detectors, etc.) to prevent mass shootings has cost the federal government at least $811 million since the Columbine High School massacre in 1999. That sum is rivaled by investments being made at the state and local level, with many school districts buying "bulletproof" backpacks for students, purchasing police officers' time to practice "active-shooter" drills, and testing out "active-shooter detection" systems that costs as much as $100,000.

By 2017, one research firm predicts, school security systems could be a $5-billion-a-year industry.