title: Add multiple geom_line to ggplot
body: <p>The <code>geom_line</code> CUR_MTH_UNEARN_REV_EUR is plotted correctly as a numeric. My goal is to add a second numeric <code>geom_line</code> (i.e., CUR_MTH_EARN_REV_EUR). Here's the code:</p>
  
  <pre><code>library("ggthemes")
  library("gridExtra")
  library("grid")
  
  p = ggplot(f, aes(DTE_OF_REPORT_EUR, CUR_MTH_UNEARN_REV_EUR, label=(CUR_MTH_UNEARN_REV_EUR)))
  + geom_point(size=ifelse(f$CUR_MTH_UNEARN_REV_EUR&lt;8.0, 11, 5), color=ifelse(f$CUR_MTH_UNEARN_REV_EUR&lt;8.0, '#CC0000', 'black')) 
  + geom_line(size=2,aes(group=1)) + geom_rangeframe() + theme_wsj() 
  + theme(axis.text.x=element_text(angle=50, size=20, vjust=0.7)) 
  + geom_smooth(aes(group=1), method="loess", colour = "#CC0000", lwd=2) 
  + geom_text(aes(label=CUR_MTH_UNEARN_REV_EUR), hjust=-0.5, vjust=0.5, fontface="bold") 
  + ggtitle("Unearned Revenue by Service Code 'BS', in CSG Months, Jul. 2014-Aug. 2015") 
  + theme(plot.title = element_text(lineheight=.8, face="bold"))
  
  p
  
  Text1 = textGrob("Source: Revenue Assurance and Quality Control", gp=gpar(fontsize=7))
  p2 = p + annotation_custom(grob = Text1, ymin = -0.2, ymax = -30)
  
  p2
  
  format(round(f$CUR_MTH_UNEARN_REV_EUR, 2), nsmall = 2)
  f$ScoreRounded &lt;- round(f$CUR_MTH_UNEARN_REV_EUR, 1)
  f$DTE_OF_REPORT_EUR &lt;- factor(f$DTE_OF_REPORT_EUR, levels=unique(as.character(f$DTE_OF_REPORT_EUR)))
  </code></pre>