Update/errata 9/7/2021: Though there are indeed many domains with an SPF record in the CZ ccTLD, the numbers mentioned bellow turned out to be incorrect, due to a calculation error on the part of my source, which only came to light late last night. It turns out that at the time of the scan, there were approximately 1.1 million domains without an SPF record, and only about 300k had the record set (i.e. the ratio was reversed). These numbers are still interesting, though much less optimistic than the originally reported ones...