Over 900,000 people reached the continent and 3,563 went missing or drowned trying to make the journey, monitors say.

More than 900,000 refugees and migrants have arrived in Europe since January 2015, and over 3,000 have drowned or gone missing during the same period, according to the UN and an organisation which monitors the migration flow.

Since January 2015, at least 907,712 refugees and migrants made the journey to Europe, including 878,495 who have arrived by sea, the International Organization for Migration (IOM) said on Tuesday.

That means that almost 97 percent arrived by sea.

At least 3,563 people have gone missing or drowned trying to reach Europe, the IOM said.

The UNHCR put the number of arrivals by sea at 886,262, and 3,515 reported missing or dead.

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The IOM and UNICEF said that children accounted for 20 percent of those arriving in 2015.

The share is greatest along the Eastern Mediterranean route from Turkey to Greece and through the Western Balkans, where children make up over one-quarter of arrivals.

In October, more than 90 children died on their way to Greece, and in the past week, nine of the 12 deaths on this crossing were children, the IOM said.

Mostly Syrians and Afghans

Along the journey, children are also more at risk of illness and injury, as well as exploitation, separation from family, kidnapping and trafficking.

Greece has seen the largest number of refugees arriving by sea, where at least 738,465 refugees have arrived since January this year.

The majority of those arriving in Europe by sea come from the world’s top 10 refugees-producing countries, the highest being Syria and Afghanistan.

On Wednesday, the EU struck a deal with Turkey in Brussels that aims to limit the flow of refugees into the continent.

The agreement includes providing Turkey with $3.2bn, along with closer ties with the EU in return for handling the refugees from war-torn countries on its territory.

The UNHCR reported in June that the worldwide displacement was at the highest level ever recorded, in which, by the end of 2014, a staggering 59.5 million people were forcibly displaced.

It also said that globally one in every 122 humans is now either a refugee, internally displaced or seeking asylum.

Since 2011, the main reason for such a rise in figures has been the war in Syria, now the world’s single-largest driver of displacement.