You can find a statistic to suits your ends Jason, it still misses the point. I accept you are bound by regulation to test under the German system, but that doesn't surprise me, despite the evidence, hip testing is still extremely widely and generally accepted, I absolutely accept you must do it, I question if it is of any benefit at all.
Working spaniels and show spaniels are all lumped under one breed remember. As for moving with times, the outdated, ineffective x-ray system which has done nothing to change anything about hip diplasia is now about 4 decades old, my contention is it is about time people looked at the overwhelming facts and moved with the times.
Here's some more info to consider... (The point of all this is to highlight that there is very little definitive in any way shape or form when it comes to HD.!
Bad hips and knees: Is it hip dysplasia or a torn cruciate ligament?
Interesting that this study concludes....
Wayne H. Riser, W. Harker Rhodes, and Charles D. Newton
Section One: Theories of Pathogenesis
Canine hip dysplasia is a complex disease. It is a concentration of factors from a pool of genetic weaknesses and environmental stresses that fall into a programmed pattern of progressive remodeling and degenerative joint disease. The degree of involvement varies from minute changes in bone structure to total destruction of the hip joint. Investigators have searched intensively for genetic, chemical, and metabolic defects, but the cause has remained obscure.
Hip dysplasia affects humans and all other domestic mammals. In humans, 1.3 children in 1000 are affected. In dogs the prevalence may run over 50% in large dogs if control measures have not been practiced. Few data are available on the prevalence of hip dysplasia in other mammals, but it is thought to be low. The disease is undoubtedly rare in undomesticated animals.
No specific genetic pattern of inheritance has been demonstrated in this variable disease. It has been demonstrated that both genetic and environmental influences contribute to development, regardless of the species affected.(15,31, 32,40,74,76) Consequently, the disease has been designated as polygenic or multigenic.(28) As in most polygenic diseases, there are both major and minor causative factors. There is no evidence that a primary defect of bone exists but rather the disease is a failure of the muscles and other soft tissues to hold the hip joint in full congruity.(31,32) This is further supported by the fact that bony dysplasia can be increased, decreased, or prevented by controlling the degree of joint instability and incongruity.(53) No other malformations are associated with the disease.(79) A causal relationship between muscles and soft tissue defects or pathologic changes other than lack of muscle mass or strength has not been established.(40,41)
Experimentally, hip dysplasia may be produced in many ways.(43,56,74,76,87,88) These include any circumstances that contribute to an unstable hip joint, namely, adductor forces, lack of muscle strength, chemical relaxation of the pelvic soft tissues, traumatic injury to the hip joint, and overloading of the joint by weight. Hip dysplasia is a concentration of factors from a pool of genetic weaknesses and environmental stresses that fall into a programmed pattern of progressive remodeling and degenerative joint disease.
What I begin to find as I research more and more is that they reason we see such a low incidence in working breeds is the strength and development of muscle, ligaments etc in having a high level of fitness. Wirehair may have been closer to the truth than I first thought. It may well be that it is not that the working breeds are genetically free of HD, but simply properly developed and fit.
The fact we know bugger all remains and anyone trying to claim something definitive in its regard is going against all of the scientific information we have at hand.