factory reset date ??

hello all
is there any why to know the date for last factory reset ??

i found this

Have a look at Cache/Root/recovery/last_log

At the top you will see
Starting recovery on <timestamp>

then further down you will see something like

Command "/sbin/recovery" "–wipe_data"

and still further

– Wiping data…
Formatting /data…
Formatting /data…
Creating filesystem with parameters

This timestamp relates to the factory reset. At least this was the case with a Samsung Galaxy S3 GT-I9300 running OS 4.3 (Jelly Bean) discovered by testing with a reference device.

but nothing useful !!

so where i can find this dates in my physical dump and extract them manually !!

any help here ??