ggplot2 – How to make y-axis in ggplot range from 0% to 100% in R? [image and code included]

I have this plot and it seems that my minimum value is 65%, I would like my y-axis to be from 0 to 100% instead. Here is the plot and below the plot is the ggplot code
enter image description here

ship_mode_summary_delv_performance_plot_ontime <- ggplot(ship_mode_summary_delv_performance, aes(x = FSCL_WK_NBR, y = on_time))+
  geom_line(aes(y = on_time), color = "#336666", size = 1.10, show.legend = TRUE) + 
  theme_economist()+
  scale_y_continuous(breaks=seq(0,1,.05))+
  scale_x_continuous(breaks=seq(1,46,1))+
  xlab("Delv Fsck Wk Nbr") +
  ylab("On-Time% Avg") +
  ggtitle("Delivery On-Time%")+
  theme(plot.title = element_text(size=12), axis.text=element_text(size=11), 
        axis.title=element_text(size=11), strip.text = element_text(size=11),
        axis.title.y = element_text(margin = margin(t = 0, r = 20, b = 0, l = 0)),
        axis.title.x = element_text(margin = margin(t = 20, r = 20, b = 0, l = 0)), 
         legend.position="bottom", legend.title = element_blank(), legend.text=element_text(size=14))