Aws data transfer rate: $0.010 per GB - regional data transfer - in/out/between EC2 AZs or using elastic IPs or ELB

AWS have charged me $0.09 for data transfer. below is the line from bill details which shows the data usage of 8.988 GB and charge of $0.09

$0.010 per GB - regional data transfer - in/out/between EC2 AZs or using elastic IPs or ELB 8.988 GB    $0.09

But in my region all servers are in the same region and same availability zone.i am also not using ELB. Is this charge apply for elastic IPs which i am using for accessing web site though browser and for doing ssh?? if yes then why AWS have not charged me for data transfer rate in the previous month bills.