I am in Agreement with Jim. It would largely depend on how different companies classify the different costs within their accounting system. Even within the same company, there may be differences between different book-keepers. Such a figure, if they are available would be as good as nothing.
If you are presenting to management hoping to get their attention, why not express it as a percentage of 'net profit'. First, net profit is usually a small fraction of sales and if you do it this way, you amplify the seriousness of the situation because the resultant figure will be much higher. Next, everybody will realized what percentage of net profit had been fore-goned due to external failure cost.