#######################################################
prop.data <- rbind(cbind(google.by.week(d), subset="All Email"),
- cbind(google.by.week(d[d$replied]), subset="Emails with Replies"))
+ cbind(google.by.week(d[d$replied]), subset="Email with Replies"))
pdf(file="emails_gmail_prop_over_time.pdf", width=10, height=8)