[greendestiny]

If you only publish results p < 0.05 then you can't say what percentage are due to chance. It could be all of them. All it tells you is how many experiments would get that significance level through chance. To know the number of results that are simply due to that effect you'd have to know the prevalence of actual positive results (ie not due to chance). If a actual positives are common then it could be much lower than 5% reported results due to chance, if actual positives are impossible then it could 100% due to chance.