What determines keypoint order in blob detector

I need some help interpreting blob detection results. What criteria determines how keypoint results are stored? Below, are the binKeypoints stored according to size for example?

Ptr<SimpleBlobDetector> detector = SimpleBlobDetector::create(params); 
detector->detect(matImage, binKeypoints);

                               float a_img = binKeypoints[0].pt.x;
				float b_img = binKeypoints[0].pt.y;
				float a2_img = binKeypoints[1].pt.x;
				float b2_img = binKeypoints[1].pt.y;
		               float c3_img = binKeypoints[2].pt.x;
				float c3_img = binKeypoints[2].pt.y;

since this is based on findContours() , it will give you points in the order their resp. contours are found.
(i have no idea about this, but there definitely is no sorting of any kind after that)