Bandwidth Usage

I am not sure to understand the bandwidth usage. For example one site does :
Bandwidth Usage 3025 (MB) 1000 (MB)
Is it using 3025 MB right now or since it has been created ? 20 visitors a day is not that much… I know using the image optimiser increases the bandwidth usage. Should I be aware of this ?

Yes, it is since the day website has been created.