How to track and report which data is used or accessed the most for a site on an internal network? I have a Drupal site set up on Solaris 10. 

I made custom PHP file to allow users to pass parameters in URL to retrieve feedback in xml format, and a couple of views to display data in table format.

Is there a way to track which data is used or accessed the most and display it in a report? So I can get rid of the data less frequent used.

Note: The site I built is for internal network, so the outside world doesn't have access to it (and therefor I cannot use Google Analytics).
Have a look at the Visitors module. Here are some reports you get from it:


  
  View pages that have recently been visited.
  View pages that have been hit frequently.
  View pages count per month, day of month, day of week, hour.
  ...
  


Especially these reports should be what you're looking for, which also includes hits for paths corresponding to a view, such as the one with path charts/examples/views:


Top pages (table with columns Title, Path and nr of Hits). Here is an example of this report:


Recent hits (table with columns Date of visit, Title, Path and User ID of the visitor). Here is an example of this report:



If you follow any of the "details" links in the example above, you'll get something that looks as in this example:




Checkout the above (source) links to get an idea of which data are available.

The demo site contains some sample reports (charts) available to anonymous users also. Any visits to a Views related path will be reported in the Recent hits module. This demo site also shows some additional blocks with reports also created by the Visitors module module.

You may also want to look at the visitors_schema to get an idea of the data that actually get logged (recorded) by this module.

In case it's not a perfect fit, it's probably a very good starting point for some custom reporting. Either via a custom module that would simply have to query the data maintained by the Visitors module. Or via a straight forward custom report created with the Forena module.

Disclosure: I'm the maintainer of the Visitors module,
and co-maintainer of the Forena module.