Question

When I manually add the following labels with (axis(1, at=1:27, labels=labs[0:27])):

> labs[0:27]
 [1] "0\n9.3%"  "1\n7.6%"  "2\n5.6%"  "3\n5.1%"  "4\n5.7%"  "5\n6.5%"  "6\n7.3%"  "7\n7.6%"  "8\n7.5%"  "9\n7%"    "10\n6.2%" "11\n5.2%"
[13] "12\n4.2%" ........

I get the following:

How do I force all labels to be drawn so 1,3,5,6, and 11 are not skipped? (also, for extra credit, how do I shift the whole thing down a few pixels?)

Answer 1

?axis tells you that:

The code tries hard not to draw overlapping tick labels, and so will omit labels where they would abut or overlap previously drawn labels. This can result in, for example, every other tick being labelled. (The ticks are drawn left to right or bottom to top, and space at least the size of an ‘m’ is left between labels.)

Play with cex.axis so that labels are small enough to fit without overlapping

labs <-c("0\n9.3%","1\n7.6%","2\n5.6%","3\n5.1%","4\n5.7%","5\n6.5%","6\n7.3%",
         "7\n7.6%","8\n7.5%","9\n7%", "10\n6.2%","11\n5.2%","12\n4.2%",12:27)
plot(1:27,xaxt = "n")
axis(side=1, at=1:27, labels=labs[0:27],cex.axis=0.35)

If you widen you graph (manually by dragging or programmatically), you can increase the size of your labels.