BANNOCKBURN, IL -- Some 85% of electronic components placed are surface-mount and 15% are plated through-hole, a new IPC study of EMS companies has found.

The median number of PCB assemblies completed by responding companies last year was 172,356 and the median number of components placed was 22.5 million.

A total of 41 EMS companies responded to the survey, IPC said.

The survey, "Quality Benchmarks for the Electronics Manufacturing Services Industry for 2013," covers production data, assembly attributes, yields, defect rates (DPMO), customer returns, supplier performance, customer satisfaction and certification data.

Survey respondents were from North America, Europe and Asia and had annual sales ranging from under $10 million to over $1 billion.