HOUSTON – MS-13 gang members are being caught entering the United States illegally in growing numbers.

READ: Inside the fight against MS-13 in Houston

Customs and Border Protection agents have apprehended more than four times as many MS-13 members so far this fiscal year than last year.

In April, Channel 2's Jacob Rascon traveled to El Salvador, where MS-13 rules the streets with brutal force.

Earlier this month, he revealed how law enforcement in the Houston area is working undercover to track down and arrest MS-13 gang members responsible for murders and kidnappings.

Here is a by-the-numbers look at the gang:

About 6.3 million people live in El Salvador (there are about 6.4 million in greater Houston).

Approximately $2 million are extorted every month from Salvadorans by MS-13 members, according to prosecutors there.

Approximately 50,924 people were apprehended by Customs and Border Patrol in April 2018, compared with 15,766 people the same month last year. March numbers are similar. This is according to CBP. The overwhelming majority are not gang members, but gang members are found crossing into the U.S. illegally every day.

There are approximately 40,000 MS-13 members in El Salvador, according to its attorney general’s office. Tens of thousands more operate across Central America and Mexico.

There are approximately 10,000-15,000 MS-13 members in the United States, active in more than 40 states, according to the Department Of Justice.

There were 6,656 homicides reported in El Salvador in 2015. That number has dropped by more than 1,000 every year since, except in 2018, when homicides have increased.

There are 800-1,200 MS-13 members in the greater Houston area, according to the FBI.

There have been approximately 227 MS-13 members caught at the U.S. border so far this fiscal year -- a pace not seen since 2014, according to Customs and Border Protection data. They sneak into the country, or they pose as unaccompanied minors or fathers with small children. Law enforcement sources told KPRC that nearly every MS-13 member arrested for a violent crime in the greater Houston area since 2014 has protected unaccompanied minor status.

There are 249 MS-13 “clicas” that operate in El Salvador, led by “Palabreros.” These are governed by 48 “programas,” led by “Corredores.” They collect extortion money and are governed by 15 “ranfleros,” or top leaders of Mara Salvatrucha, one for every letter of the full name of the gang. Additional ranfleros operate inside El Salvador prisons. Orders to execute in the states oftentimes come from El Salvador.

150 MS-13 members have been caught trying to cross the border in the Rio Grande sector so far this fiscal year. That’s more than four times as many as were caught last fiscal year, to date, in the same sector, according to Border Patrol data.

Sixty years is the maximum punishment in El Salvador for any offense, including multiple homicides, according to the AG’s office. Longer prison sentences are handed down, but only 60 years will be served.

Fifteen years is the maximum punishment for minors in El Salvador for any offense, including multiple homicides. MS-13 members are typically serial killers, and it’s not uncommon for a 18-year-old veteran MS-13 member to have killed 20 people. They usually join the gang as teenagers, or younger.

Fourteen agencies work together at Houston’s Texas Anti-Gang Center, the first in the state. There are now six TAG centers in Texas, with a seventh scheduled to open in late 2018.

Seven years is the minimum sentence for homicide for minors in El Salvador.