99.9% of the times those “unknown”, “private”, “nobody-else-but-me” websites, are not actually private.
It’s running on a public server, a public domain. Bots, automated programs, and something like that, will find your site eventually. And they generate a ton of hits.
I left 0.1% for that the counter is actually wrong but this is highly unlikely.
Free hosting doesn’t keep any logs unfortunately so you cannot get to know what exactly is generating these hits.