I've read that restaurants as a whole usually spend 30% of the price on ingredients, and the rest is staff and rent and other miscellaneous items. Buffets work

I've read that restaurants as a whole usually spend 30% of the price on ingredients, and the rest is staff and rent and other miscellaneous items. Buffets work because even if people eat more, the restaurant as a whole operates more efficiently(no individual servers). I don't know what the percentage is for high-end restaurants. Do you think it's higher or lower?