Afghan migrants account for nearly fifty percent of inhabitants at Bulgaria's state-run reception and registration centers, officials said.
Syrian and Iraqi protection candidates make up for around 40 percent, each group taking nearly half of the figure.
Statistics from the Bulgarian Interior Ministry, released on Wednesday, show that facilities administered by both the Interior Ministry and the State Agency for Refugees are operating beyond their capacity to accommodate arrivals.
At the ministry centers in Busmantsi and Lyubimets there are 1,608 inhabitants as of November 30, above a maximum capacity of 1,200.
Facilities with the State Agency for Refugees are also overcrowded, with 5,190 beds available but 5,527 migrants having been accommodated, or 106 percent of the maximum capacity.
As many as 1,178 people were accommodated in refugee agency centers in October, while 2,400 left voluntarily, the figures suggest.
Since January, some 16,800 people have sought protection from the agency, but the vast majority of them, or some 12,500, have left the centers, prompting authorities to terminate their protection requests.