(VOA) Muslim militants tried to create areas governed by Islamic law long before the Islamic State group began its campaign in the Middle East.

Some groups supported attacks on governments that they did not believe were enforcing Islamic law. Others believed they should work to weaken Western countries — especially the United States.

In the 1990s the terrorist group al-Qaida won the debate. It supported attacks on the United States, including those that took place on September 11, 2001.

But al-Qaida’s power has lessened in recent years. Terror groups have formed that are working to weaken government in the Middle East, South Asia and North Africa. These groups include the Islamic State, which has supported attacks on neighboring countries — including those led by Muslims.

The result is that most of the victims of terrorist attacks by Muslims over the past 15 years have been other Muslims. Recently, a 14-year-old Islamic State suicide bomber attacked a Kurdish wedding in southeastern Turkey. More than 50 people were killed.

Richard Bulliet is a retired professor of history at Columbia University. He says most non-Muslims should not be worried about terrorism.

“I understand why the media cover terrorism in the West so closely, and I understand why people who follow these events become so frightened, but, objectively speaking, the threat of terrorism is not very great.”

Between 2001 and 2015, there were 167,221 victims of terrorism. About 98 percent of them took place outside the United States and Western Europe, according to the University of Maryland Global Terrorism Database.

The database is supported by the United States government. It is the largest public collection of information about terrorist attacks in the world.

The database does not record the religious belief of victims. However, it has gathered information about attacks in 25 Muslim-majority countries from Iraq to Malaysia. The information shows that 75 percent of all deaths from terrorist attacks from 2001 to 2015 took place in those countries.

During that time, there were 3,689 deaths in the United States and Western Europe from terrorist attacks. This includes 2,977 from the September 11, 2001 attacks. That is 2.2 percent of all terrorism-related deaths during that time.

Not all victims of terrorism in Muslim-majority countries are Muslims. Victims have included Christians, Yazidis and other minorities. There also have been many non-Christians among the victims of terrorist attacks in the United States and Western Europe.

Michael Jensen is the data collection manager for the Global Terrorism Database. He says it is safe to assume that the majority of victims of terrorist attacks in Muslim countries are Muslims.

Driven by more than religion

Information in the database shows some countries have many victims while others have very few. More than 50,000 have been killed in Iraq. But only six people have been killed in Malaysia in terrorist attacks in the past 15 years.

The reason for many of the attacks is not clear. Jensen says the large number of victims in Muslim countries compared to those in non-Muslim countries suggests that the reason is not limited to religion.

“It has to be something else,” he says.

Researchers at the Institute for Economics and Peace have looked for patterns in the Global Terrorism Database.

They have found two things common to countries where there is terrorism. Their research shows that 92 percent of all terrorist attacks in the past 25 years have taken place in countries with state-sponsored political violence. And 88 percent of attacks have taken place in places where violent conflicts are happening.

In most Muslim-majority countries with a high level of terrorist activity, one or both of these problems are present.

Iraq may be the strongest example of a country with a long history of state-sponsored violence and political conflict.

Since the 1990s terrorists have sought to oust governments in the Middle East, South Asia and North Africa.

Jensen said that in Muslim-majority countries, militants often attack citizens and property, security forces and government and diplomatic officials and institutions.

“I think in a majority of cases where Muslims are victims of terrorism, they’re largely targeted not because they’re Muslim but because they’re police officers or soldiers or happen to be in a public place,” Jensen said.

He said disputes between Sunni and Shi’ite Muslims is a major source of conflict. About 10 percent of the 1.7 billion Muslims in the world are Shia.

Professor Bulliet says Shia are being attacked by Sunni extremists from Iraq to Pakistan because they are considered a heretical minority.

Bulliet says the conflict is part of a struggle for power in majority-Sunni societies. He says those societies have still not decided what power will be held by political and religious officials.

He adds that it is still not clear in those societies what the relationship is between religion and the modern world. He says these questions have been unanswered for many years.