The U.N. refugee agency says the number of migrants crossing the Mediterranean Sea to southern Europe was more than 80 percent higher in the first half of 2015 than a year earlier, while the number of deaths soared.

The U.N. High Commissioner for Refugees said Wednesday data from Greece, Italy, Malta and Spain showed 137,000 migrants arriving between January and June — up from 75,000 in the first half of last year, an 83 percent increase. One-third were from Syria, while Eritreans accounted for 12 percent of the new arrivals and Afghans 11 percent.

UNHCR says the number of people who died making the risky crossing totaled 1,867, up from 588 a year earlier. However, it said there was a dramatic drop after an unprecedented 1,308 people died in April.