I used to use the total_items function in Omeka 1x to display a count of all public Items on my theme home page. Example:
<?php echo 'Total casualties posted to date: '. total_items() .'.'; ?>
Functions have changed in 2.0. I see that the new function is total_records and that I am supposed to reference a recordType. I am a bit lost on the recordType and if I need to first declare that function.