+ labels=c('Release', '3.0', '3.1', '', '3.2', '3.3', '4.0', '4.1', '4.2', '4.3'))
+
+#tstamp_20041112 <-abline_at_date("2004-11-12", col='grey60', lty=2, height=10)
+#tstamp_20050301 <-abline_at_date("2005-03-01", col='grey60', lty=2, height=10)
+#tstamp_20050615 <-abline_at_date("2005-06-15", col='grey60', lty=2, height=10)
+#tstamp_20051023 <-abline_at_date("2005-10-23", col='grey60', lty=2, height=10)
+#tstamp_20070101 <-abline_at_date("2007-01-01", col='grey60', lty=2, height=10)
+#tstamp_20070501 <-abline_at_date("2007-05-01", col='grey60', lty=2, height=10)
+#tstamp_20080601 <-abline_at_date("2008-06-01", col='grey60', lty=2, height=10)
+#tstamp_20080815 <-abline_at_date("2008-08-15", col='grey60', lty=2, height=10)
+#tstamp_20090501 <-abline_at_date("2009-05-01", col='grey60', lty=2, height=10)
+#tstamp_20100201 <-abline_at_date("2010-02-01", col='white', lty=2, height=10)
+#
+#
+#text(x=c( tstamp_20041112+(tstamp_20050301-tstamp_20041112)/2,
+# tstamp_20050301+(tstamp_20050615-tstamp_20050301)/2,
+# tstamp_20050615+(tstamp_20051023-tstamp_20050615)/2,
+# tstamp_20051023+(tstamp_20070101-tstamp_20051023)/2,
+# tstamp_20070101+(tstamp_20070501-tstamp_20070101)/2,
+# tstamp_20080601+(tstamp_20080815-tstamp_20080601)/2,
+# tstamp_20090501+(tstamp_20100201-tstamp_20090501)/2 ),
+# y=c(15),
+# labels=c('3.0', '3.1', '3.1S', '3.2', '4.0', '4.2', '4.3'))