Unusual small amount of bounced emails in a campaign

Unusual small amount of bounced emails in a campaign

We have a recent campaign out, with a target of quite a number of email addresses.
We have 0 bounced so far, and wonder how long it usually takes before Zoho Campaigns report a "bounce".

It seems unusual that we have 0 bounced. We have had another campaign previously, and had only 1 bounce. We know however on some of the emails that the person has left the company we are trying to send the email to, so it sounds strange that the bounce list is so small. Any advice/comments you can share with us?