new emails in dock

My Macbook pro - less than 3 months old - crashed badly, and I had to re-install the OS (Yosemite upgraded to el capitan) , and use my time machine back up from an external hard drive to return the data. This was all done through apple support. Since doing it, I am having a few small problems. One is the mail icon in my dock. I used to see the number of unread mails. It's suddenly stopped showing. Does anyone have any ideas on how to get the to show again?

Thanks.