I just counted off 10 breaths in one minute.
10 x 60 = 600 breaths per hour
600 x 24 = 14,400 breaths in a day
Let's go a little further and assume I breathe faster when I'm excited, etc.
A good estimate is 25,000 breaths a day.
25,000 x 365 = 9, 125,000 million breaths per year!
I would have to live to 109 years of age to pump out those billion breaths.
I'm still counting.
BTW - A billion pennies (to put a billion in perspective) is $10 million dollars. See the picture to get an idea of what a billion pennies looks like.