For the counter to count visits to all pages within a single site, install the counter code issued for this site on these pages. This means that you do not have to register each page separately.

Likewise, you do not need to register 2 sites if one of them is a sub-domain of the other but both have the same content. For example: http://www.domain.com and http://domain.com differ only in the prefix www. It is enough to register only one, for example http://www.domain.com.