Nigeria has topped the list of countries with the most trafficked women to Switzerland, a position it shares with Hungary, a new reports has shown, reports SwissInfo.

Last year, the proportion of human trafficking victims who are also asylum seekers tripled in the Zurich region, according to annual figures released on Tuesday.

The FIZ Advocacy and Support for Migrant Women association, located in Zurich city, handled 228 cases of human trafficking in 2017, according to its report, published on Monday.

The proportion of victims that were also asylum seekers rose from 10% to 34%, the report found.

This significant increase has also influenced the overall demographics of human trafficking. Since 2008, a clear majority of human trafficking victims in Zurich came from Hungary; however, the number of victims from Nigeria has increased steadily since 2016, and last year the West African country was on par with Hungary with 15% of new cases coming from each country.

Of the 228 cases handled by FIZ last year, 111 were new, and 117 concerned victims of previous years. Of the new cases, one third concerned asylum seekers, one tenth of them involving minors. Around one-quarter were involved in sex work.

In southern Switzerland, notably Lausanne, Nigerian women were again the most affected, and again a sizeable number were asylum applicants.

According to the Romandie Association for the Victims of Trafficking and Exploitation (ASTREE), of the 49 women helped by their canton Vaud branch, 11 were Nigerians, while 16 were asylum seekers. Some 37 of the women were victims of forced prostitution.

In Geneva, where the Protestant Social Centre released their figures, 38 women were helped last year, four of them from Nigeria.

Switzerland is an important transit and target county for people smugglers, the Swiss Coordination Unit against the Trafficking of Persons and the Smuggling of Migrants said on Tuesday.

Most migrants are smuggled through the Balkan countries, while those who have survived the perilous journey across the Mediterranean to Italy will find their way into Switzerland via Milan, the unit observed.

The Italian-speaking canton of Ticino is described as an “entrance door” into the country. But since summer 2013, Swiss-based people smugglers have increasingly been using the Geneva region as well.

The most common place of origin for both the smugglers and their victims was found to be Kosovo. Many also come from the Near East, Middle East and Eritrea, with increasing numbers also hailing from China, Sri Lanka and some areas of Africa.

A poll of asylum seekers in Switzerland found that 80% had used people smugglers to get into the country, the report said. That more and more migrants were choosing this option was due to the stricter asylum policies in Europe, it added.

It did note, however, that it was overall very difficult to calculate how many people were trafficked through and into Switzerland – and Europe – per year.