Installation :-

Installation is very simple , just download the package and unzip

•  wget http://jimsun.linxnet.com/downloads/pflogsumm-1.1.1.tar.gz
•  tar -zxf pflogsumm-1.1.1.tar.gz
• chown root:root pflogsumm-1.1.1

Generate the statistics  :-

#  cat /var/log/maillog | ./pflogsumm.pl

ref: http://adminlogs.info/2012/07/22/how-to-get-mail-statistics-from-your-postfix-mail-logs/