Yuck, etc.

Hi,

I have a couple of questions about the word 'yuck' (and a few other similar interjections).

(1) If we take the interjections yuck - bleck - blech ... I guess the first of the trio is, by far, more common than the other two in modern English? Having said that, yuck and bleck seem to have been more or less "equally common" until the last quarter of the 20th century (if I am interpreting the Google Books Ngram graphs right...). And then -all of a sudden - yuck began sky-rocketing for some reason... Go figure...

(2) No matter how antiquated the interjections bleck and blech may be today... how would you pronounce them?
Is it true that 'ch' in blech is pronounced like 'k'?

Thank you for your help!