Statcounter's suggested disclaimer is reproduced fully below.
Statcounter is an online service which helps us to understand our visitors; for example, how visitors find our website, how long they spend on our site, which web pages they are most interested in etc. We use Statcounter because better understanding how visitors are interacting with our website helps us to improve the content, design and functionality of our site. This allows us to offer a better online experience to our visitors.
Time and date of visit (this can help us to identify and plan for busy periods on our website)
IP address (this is a numerical label assigned to a device by an Internet Service Provider to enable the device to access the internet)
Browser and Operating System (this can help us to make sure that our website functions correctly in the browsers/operating systems used to access our site)
Device Information e.g. device type and screen size (this can help us to make sure that our website functions correctly in the devices used to access our site)
Referring Data e.g. a search engine link (this can help us to understand which search engines are helping visitors to find our website)
Furthermore, when you visit our website, a Statcounter cookie (called "is_unique") may be placed in your browser. This cookie is used only to determine whether you are a first-time or returning visitor and to estimate unique visits to the site.
You can learn more about cookies from Statcounter and set your browser to refuse the same here: