It all comes from the _connect VST.
The value "connections" on the dashboard screen is calculated as:
for each dictdb._Connect no-lock where _Connect-usr <> ?:
tt_Dashboard.con_total = tt_Dashboard.con_total + 1.
So you can think of it as "total active connections".
Generally speaking you will find many cases where "adding up the numbers" will not equal 100% (or the equivalent) because many connection types will be double counted.
For instance, a remote connection could be either a 4gl connection or a SQL connection.
To explain apparent discrepancies in the numbers I would need to see all of them.