How to find database growth on a Monthly Basis

SQL query to find database growth month wise and year.  

select to_char(CREATION_TIME,'RRRR') Year, to_char(CREATION_TIME,'MM') Month, round(sum(bytes)/1024/1024/1024) GB

from   v$datafile

group by  to_char(CREATION_TIME,'RRRR'),   to_char(CREATION_TIME,'MM')

order by   1, 2;

Sample Output:

YEAR MO         GB

---- -- ----------

2019 02         96

2019 03         65

2019 04        239

2019 05         32

2019 06         64

2019 07         95

2019 09        315

2019 10         31

2019 11        375

2020 04        313

10 rows selected.