Calculate/identify no of datafiles required for a table partition

Hi Team,

We have a table which is about 20+ TB in size, although the actual data is 3+ TB, the LOB segments are about 16 TB. We are planning to do annual partition on the table/LOB segments.

However we would like to know how many datafiles have to be created for each year (annual partition). Is there a way to find this information from any dictionary tables (dba_segments, dba_tablespaces, dba_data_files?)

We tried to get count of datafiles for each year from v$datafile.creation_time, but since the DB was created recently we are having challenges to get the exact counts.