I am using the Precision Time software. We (my father and I) are checking each day the accuracy of the CMOS clock of our computers (not only at home). For a week it is always exactly matched, but on Tuesday evening it is alway ahead of the atomic clock. We noted last week 10sec and the week before 12sec. The difference is always about 8sec since the start of the year. In december the difference was 5sec.
So. 6x8+10+12=1':10" slowing since the start of the year, if the navy sets it's atomic clock correctly to the slowing rotation. If not, the difference can be larger.
I already told our measuring method to others in Hungary here. They have started to check the atomic clock, too.
Offered from Hungary.