Resampling with replacement on a binary (0, 1) dataset to get Cis

...is it possible to do that?

I apologize for something that must be a very trivial question for  
most of
you but, unfortunately, it is not for me.
A binary variable is measured, say, 50 times each year during 10  
year. My
interest is focused on the percentage of 1s with respect to the  
total if
each year.
There is no way to repeat those measure within each year and getting  
the CIs
by the "normal way".
By the way, it would be important to get even a rough estimate of  
the CIs of
these estimates (/n/1//n/1+/n/0).

In case this is not a blasphemy, how might be done in R?

Thanks in advance for any help