If you're down to counting pages like this, it's time to get additional pages added. Sometimes countries can have weird rules about the amount of blank space required and sometimes things end up taking more space than you expect--either due to poorly placed stamps (e.g., the officer who just picks a random page and stamps in the middle over multiple boxes) or to unexpected events (once leaving a Schengen country mechanical difficulties ended up in my going through passport control seven times--four outbound and three cancellation stamps of the outbound stamp;though the officers got used to seeing us and weren't really examining passports after a while, the stamps took up quite a bit of space).