Oracle Database Discussions

I want to calculate the time my database was up or down for the previous month.
I know V$INSTANCE can give me the startup_time, but this time is the last startup time. I need to know the total time my database was running for the previous month.
Example, previous month had 31 * 24 (days * hours) = 744 hours, out of this how many hours my database was down or up, I cannot use the server time as the server could be up but not the database.

Is there any view in the database I can check?

Version:
Oracle Database 10g Enterprise Edition Release 10.1.0.4.0 - Prod
PL/SQL Release 10.1.0.4.0 - Production
CORE 10.1.0.4.0 Production
TNS for 32-bit Windows: Version 10.1.0.4.0 - Production
NLSRTL Version 10.1.0.4.0 - Production

Thanks

Habeeb