What would be the correct way to extract rrd data for a certain period of time (last 7 days for example). I'm trying to extract data for the following graph http://imgur.com/a/Gw9y2, although when I open up the data in excel, I'm not able to get anything of use. 

I used this command to produce an RRD export first:

/opt/observium/scripts/rrdtoolx.py addrra netstats-udp.rrd /tmp/testrrd

after which I used:

rrdtool dump /tmp/testrrd > /tmp/rrd.xml

to get the file into an xml format, and finally I imported the xml into excel.

I'm trying to put together a list of time stamps and their appropriate data points, so for example:

time1 : 22 errors

time2: 10 errors

time3: 30 errors

....

Would it even be possible to extract this kind of data from the RRD files? 

Thanks for your help,

Austin