osm: the scaling of values - approaching the growth

[unleash]

i am pretty new to Geographic-information Systems so do not bear with me if i ask newby questions:
i am interested in gatherin information on schools Some days before i have heard that it is interesting to
have a closer look at the taginfo-site (see below): i have question: what does this mean https://taginfo.openstreetmap.org/tags/amenity=school

here we have two requests on the above site:

see the details:



593 454 - at 30 th of june
593 319
593 194
592 853
592 443 - at 24 th of june

1000 records


you see: the results differs: approx 1000 x (entries, records or some what)

question:
a. is it true that we can see the diff - that means how the entries of schools grow?
b. is there a total growth of records (!!!) of schools or does the this mean - some records have been changed!?

look forward to hear from you