i know i said i was done here ,....but -
ian where are you getting those stats? 
"Away must be found of targeting the other parties who so frequently cause
motorcycle collisions. Drivers have to be made aware of the numerous ways that
they can fail to perceive a motorcycle in the typical ROWVaccidents that are
most frequently not the fault of the rider involved. Our results suggest that
interventions should be focussed on (but not exclusively confined to) older
drivers.
If all such accidents (right of way) were to be eliminated, our results suggest a theoretical fall of
slightly over 25% in the total motorcycle accident rate.     - both from 
http://www.dft.gov.uk/pgr/roadsafety/research/rsrr/theme5/indepthstudyofmotorcycleacc.pdf
- 75% of accidents were found to involve a motorcycle and a passenger  vehicle, while the remaining 25% of accidents were single motorcycle  accidents.
 
- "In the single vehicle accidents, motorcycle rider error was present  as the accident precipitating factor in about two-thirds of the cases,  with the typical error being a slide-out and fall due to overbraking or  running wide on a curve due to excess speed or under-cornering."
 
- "Almost half of the fatal accidents show alcohol involvement" and  "injury severity increases with speed, alcohol involvement and  motorcycle size."
 
- In the multiple vehicle accidents, the driver of the other vehicle  violated the motorcycle right-of-way and caused the accident in  two-thirds of those accidents.
 
- The report's additional findings show that the wearing of  appropriate gear, specifically, helmets and durable garment, mitigates  crash injuries substantially.
 
- "Vehicle failure accounted for less than 3% of these motorcycle  accidents, and most of those were single vehicle accidents where control  was lost due to a puncture flat" and "Weather is not a factor in 98% of  motorcycle accidents."
 
- "The failure of motorists to detect and recognize motorcycles in traffic is the predominating cause of motorcycle accidents... Conspicuity  of the motorcycle is a critical factor in the multiple vehicle  accidents, and accident involvement is significantly reduced by the use  of motorcycle headlamps-on In daylight and the wearing of high  visibility yellow, orange or bright red jackets."  - from HURT report
 
The most recent large-scale study of motorcycle accidents is the 
MAIDS report carried out in five European countries in 1999 to 2000, using the rigorous 
OECD standards, including a statistically significant sample size of over 900 crash incidents and over 900 
control cases.
 The MAIDS report tends to support most of the Hurt Report findings,  for example that "69% of the OV [other vehicle] drivers attempted no  collision avoidance manoeuvre," suggesting they did not see the  motorcycle. And further that, "the largest number of PTW [powered  two-wheeler] accidents is due to a perception failure on the part of the  OV driver or the PTW rider." And "The data indicates that in 68.7% of  all cases, the helmet was capable of preventing or reducing the head  injury sustained by the rider (i.e., 33.2% + 35.5%). In 3.6% of all  cases, the helmet was found to have no effect upon head injury" and  "There were no reported cases in which the helmet was identified as the  contact code for a serious or maximum neck injury."
[10]
- from the MAIDS report
i could go on like this but cant be assed, and i think the figure your quoting is wrong, your maybe thinking 20% of injuries or death following a RTI are on motorcyclists? 
the above indicates that three quarters of accidents involving a motorcycle also involves another vehicle, and in two thirds of THOSE, the other vehicle was to blame, generally because they didnt see the motorcycle.
your stats are wrong mate, and what the others guys were asking is how you can draw a conclusion about the majority of riders being stupid when (even if your stats were accurate) its not possible to prove that from them.