[R] help with a survplot

[Jabba]

Dear useRs,

I was asked to produce a survival curve like this:

http://www.palug.net/Members/jabba/immaginetta.png/view

with the cardinality of the riskset at the bottom. 

I do not like doing it, because it doesn't add any valuable information
and because it doesn't discriminate between died and censored.

Nevertheless, is there someone able to tell me how to do it? Currently
the only way I know to it is using the text() function, but this would
make much more diffcult drawing the other annotations, I believe. 

Probably a grid viewport could serve the purpose, but i still don't know
grid. 

Thank you so much for the attention paid.

Marco Barbàra.