Tracking Oracle database growth

To calculate the Datafile Growth on a yearly basis:
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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;

YEAR MO         GB
---- -- ----------
2000 04          9
2004 06          5
2004 11          5
2005 01          2
2005 02          4
2005 06          4
2005 09         20
2005 10          2
2005 11         12
2006 01          8
2007 01          1
2007 06          8
2007 08       1490
2008 01          8
2008 02          9
2008 03         44
2008 04         22
2008 07         16
2008 09         10
2008 10         57
2009 01         14
2009 02         36
2009 04         37
2009 05         26
2009 06         23
2009 07         82
2009 08          0
2009 09         18
2009 11         36
2009 12         16
2010 01         39
2010 02         80
2010 03          6
2010 04         56
2010 05         80
2010 06        471
2010 07         36
2010 08         75
2010 09        160
2010 10          4
2010 12         38
2011 02         59
2011 04         52
2011 05         16
2011 07         78
2011 08         40
2011 09          9
2011 10         78
2011 11         57
2011 12          8
2012 01        110
2012 02        134
2012 06          6
2012 08         14


Through  OEM :
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Here are the steps to know Database growth pattern for last one month/year using OEM


1) Login to OEM and Click on the Reports Tab
2) Navigate to Reports–>Storage–>Oracle Database Space Usage path and Click on Oracle Database Space Usage link.
3) Select the Target database and here we are getting Oracle Database space usage for last one Month.
4) Also we can get one year Database growth by setting Set Time Period Button.
5) Also we can find Oracle Database Tablespace Monthly Space Usage by Navigating Reports–>Storage–>Oracle Database Space Usage path and click on Oracle Database Tablespace Monthly Space Usage link.