Young, angry, homegrown: Most terror attacks in West carried out by 'violent millennials' without IS-links

The report, presented late Thursday, found that since the so-called IS proclaimed its "caliphate" in June 2014, three years ago, 51 attacks have been carried out in the West in eight countries.

"Radicalisation and jihadist attacks in the West" was drawn up by experts at America's George Washington University, Italy's Ispi (Institute for International Political Studies) and the ICCT counter-terrorism centre in The Hague.

France was hit the hardest, suffering 17 attacks, followed by the US with 16 and Germany with seven.

The attacks - which left 395 dead and at least 1,549 wounded - were carried out by 65 assailants.

Forty-three lost their lives, 21 were arrested, and one is on the run.

The average age of the attackers was 27 years and three months. The youngest was 15 years old, the eldest 52.

Nearly all of them were men - only two were women.

Seventy-three percent were citizens of the country where they carried out the attack.

Fourteen percent were lawfully resident in the country or were legally visiting from nearby countries, five percent were refugees or asylum seekers, while six percent were in the country illegally or awaiting deportation.

Seventeen percent were people who had converted to Islam.

Eighty-two percent were already known to the authorities before their attacks: 57 percent had a criminal record and 18 percent had already spent time in prison.

Only 18 percent were foreign fighters, and in just eight percent of the attacks the order is thought to have come directly from IS leaders.

In 66 percent of the cases, the attackers had some form of connection to the Islamic State group but acted alone.

And in 26 percent of them, they had no connection with IS or other jihadist groups but were inspired by their call to arms.