[R] determine the number of digits printed into graph with "text(...)"

[Georg Ehret]

Dear R comunity,
   I am printing a number in a graph using "text(...)" -  see code
below: "fraction" is my number. I wish to print only two digits of the
number and struggle to do this... options(digit=3) does not work...
Thank you for your suggestions! Cheers, Georg.

**********************************
Georg Ehret
Johns Hopkins
Baltimore

callrates<-read.table("RSG",col.names=c("variant","callrate"))
hist(callrates[,2],breaks=100)
fraction<-nrow(callrates[callrates$callrate>=0.9,])/nrow(callrates)
hist(callrates[,2],breaks=100)
text(0.4,500,"proportion of callrates >= 0.9:")
text(0.4,450,fraction)