Just wondering what is the average distance that an average cats prefers to sleep from 'the ownser'?
Depends on many circumstances. There is no universally applicable answer to this question.
Cat preference - Some cats like snuggling up for heat. Others don't. Others only do it when it's really cold.
Human sleeping habits - Humans who often roll/move while sleeping are difficult to sleep next to; cats may prefer to stay at a safe distance so they don't have to move.
Wanting to be petted - There are clear times where my cats want or do not want to be petted. Depending on that decision, they choose to lie next to me or slightly further away from me.
Other reasons may still exist. I have listed the ones I actively know of.