Soldiers stand at the site of a gun battle in the Valley of Juarez, on the outskirts of Ciudad Juarez, February 17, 2015. Reuters

The grisly accounting continues in Mexico, as homicides hit a new high for the year in September — the third month in a row in to lodge such a record.

Nationwide, there were 2,187 homicide victims in September, exceeding the 2,155 of August and the 2,098 recorded in July. July was the first time the number of homicide victims was over 2,000 since the government began releasing that statistic at the start of 2014.

The number of homicide cases — a data point the Mexican government has released since 1997 — were 1,974 in September, which was a high for this year and the most registered since May 2012, meaning those 1,974 cases are the most recorded in a month since current President Enrique Peña Nieto took office in December 2012.

The number of homicide victims in September was a 37% increase over the number in September 2015, 1,599, and the total number of homicides recorded in the first nine months of this year, 16,747, was a 20% increase over those in the first nine months of last year, 13,938, Mexican security analyst Alejandro Hope noted on Twitter.

A woman wears a skull mask in front of the National Palace during a rally by relatives and supporters of 43 missing teacher's college students in the Zocalo, Mexico City's main square, September 23, 2015. AP Photo/Rebecca Blackwell

"Measured by daily average, September 2016 was the month with most preliminary investigations for intentional homicide since June of 2011," Hope said. 2011 and 2012 were the tail end of a period of violence that lashed Mexico starting around 2009, a few years after then-President Felipe Calderon deployed troops throughout the country to fight drug cartels.

"Let me put it this way: there were more homicides [in September 2016] than in 11 of 12 months of 2012 and in 9 of 12 in 2011," Hope added.

Mexico's most violent states have homicide totals significantly higher than the national average. Mexican government data

The 16,747 homicide victims recorded nationwide through the first nine months of this year put the country on pace to vastly exceed the 18,673 registered through all of 2015 and the 17,324 the country saw in all of 2014, returning to homicide levels not seen since 2011.

The ongoing spike in homicides is largely driven by increasing violence among organized-crime groups involved in the drug trade.

In the parts of Mexico where these groups are active, the number of killing vastly outstrips more placid parts of the country.

Mexico state, which wraps around Mexico City like a horseshoe, saw the most homicides in September, 185, though as Mexico's most populated state, with 16 million people, its homicide rates are typically high.

Southwest Mexico, however, has been a focal point of organized-crime-related violence.

Guerrero state saw 170 homicides. That number was down significantly from the 217 the state had in August, but it was still the second most in the country last month. Guerrero is home to extensive marijuana and opium cultivation, and its location on the coast and near the country's center has made it prize territory for traffickers.

It's thought regional groups, including the Guerreros Unidos gang involved in the disappearance of 43 students in September 2014, are vying for control of the state's eastern highlands, while other gangs and major cartel groups like the Sinaloa cartel and the Jalisco New Generation cartel (CJNG) are battling for control of Acapulco, a once idyllic resort city on the Pacific coast that is now one of the most violent cities in the world.

Michoacan, in southwest Mexico, saw 164 homicides last month, the second most in the state so far this year. Michoacan has long been a hotspot for cartel activity.

A map of suspected areas of influence for Mexico's drug cartels. DEA 2015 NDTA

The brutal reign of the Knights Templar cartel sparked a popular uprising around 2014, with citizen-formed auto defensas, or self-defense groups, rising up.

That uprising, coupled with a heavy federal response, undermined the Knights Templar, but since then other groups, including the ascendant CJNG, have moved in.

In recent weeks, clashes in the state have intensified, particularly in the state's central Tierra Caliente region, as remnants of the Knight Templar, elements of the CJNG, state security forces, and others clash. A government helicopter was shot down in September.

Jalisco state, just north of Michoacan, saw 123 homicides in September, its second most this year. The state is thought to be the home turf of the CJNG, but that group has clashed with the dominant Sinaloa cartel there.

Police near the covered body of a person who died after a bus was set on fire in Guadalajara, March 9, 2012. Gunmen torched vehicles and blockaded roads in metropolitan Guadalajara during a military operation to arrest two leaders of the Jalisco New Generation cartel, local media reported, saying two people had died. REUTERS/Alejandro Acosta

In September, it's believed that CJNG gunmen abducted at least one of incarcerated Sinaloa kingpin Joaquín "El Chapo" Guzmán's sons.

He was released five days later, but the incident has brought the Sinaloa-CJNG competition to the fore, and Sinaloa state, farther north of Jalisco, has seen more killings and fighting between state security forces and cartel gunmen in the weeks since.

Colima has seen a significant increase in homicides over the last two years. Mexican government data

The most shocking spike in killings has come in Colima, one of Mexico's smallest states by size and population.

Nestled between Jalisco and Michoacan, Colima is home to the port of Manzanillo and is strategically valuable to any cartel trying to move product in and out of Mexico.

Colima saw 48 homicides this September, more than double the 23 it had last September and 24 times the two killings it had in September 2014.

The state's homicide rate so far this year, 58.99 per 100,000 people, is nearly five times the national average of 12.43.

The rising violence has also affected areas savaged by drug-related violence between 2009 and 2012.

Chihuahua, which borders the US and is home to Ciudad Juarez, saw its highest number of homicides so far this year in September, with 143.

This has likely been driven by violence in Ciudad Juarez, a city of some 1.3 million people and through which highly lucrative trafficking routes pass.

Increased fighting in and around the city appears to be driven by instability within the Sinaloa cartel since Guzmán was recaptured in January as well as the reemergence of the Juarez cartel, which Guzmán's organization defeated in 2012.

The 2009 to 2012 period when the Sinaloa and Juarez cartels fought over the city made it the most violent city in the world, with more than 3,000 homicides three years in a row.

Tijuana has seen a sustained increase in homicides in recent months. Mexican government data

Farther west, in Baja California's Tijuana, which is also a valuable trafficking transit point, low-level fighting between the Sinaloa cartel and the CJNG cartel have pushed up homicide levels too.

The state as a whole saw 139 killings last month, the most this year. Tijuana itself had 80 homicides in September, the most this year as well.

This isn't to say that all of Mexico has been swept by killings.

Nayarit, tucked between Jalisco and Sinaloa on the west coast, has only had 31 killings this year.

Aguascalientes in north-central Mexico has only seen 32, and Yucatán, Mexico's far eastern state on the Gulf of Mexico, has had just 37 killings.

States like Querétaro and Tlaxcala, which both border Hidalgo, and Campeche, which neighbors Yucatán, have had single-digit monthly homicide totals for much of this year.

In response to elevated crime levels, the Peña Nieto government said earlier this year that it would send federal police and soldiers to intervene in the 50 municipalities that had 42% of the country's homicides.

Mexican President Nieto gives a speech during his proposal for energy reforms in Mexico City on August 12th. REUTERS/Henry Romero

The criteria used to structure this deployment likely left out many areas with serious crime problems, Hope argued in September.

This kind of intervention also mirrors past responses to crime, such as Calderon's massive deployment in 2007, to which several years of brutal, nationwide violence has been attributed.

"The security policy continues suffering from a deficit of imagination," Hope wrote in Mexican newspaper El Universal in early September. "While that doesn't change, we are going to continue reporting frightening numbers."