(ShareCast News) - September's daily volumes dropped year-on-year, interdealer broker Icap revealed on Wednesday, though were much improved from the historically quieter August.Average daily volume in the US treasury market of $157.4m was down 2% on September last year but up 8% from August.US repo rates were up 9% year on year to an average of $210m and up 5% on a monthly basis, while European repo volumes were down 1% on 2015 but up 8% on August.Average daily volume of $89.4m at its EBS electronic trading platform was down 9% YoY and improved 19% MoM.