How to flip axis of a horizontal barplot in ggplot2

How to flip axis of a horizontal barplot in ggplot2

References

Reference NO 1

http://stackoverflow.com/questions/15192872/how-to-flip-axis-of-a-horizontal-barplot-in-ggplot2

Reference NO 2

http://stackoverflow.com/questions/18265941/two-horizontal-bar-charts-with-shared-axis-in-ggplot2-similar-to-population-pyr

Reference NO 3

http://docs.ggplot2.org/current/geom_bar.html

Reference NO 4

http://www.ceb-institute.org/bbs/wp-content/uploads/2011/09/handout_ggplot2.pdf

Reference NO 5

http://rstudio-pubs-static.s3.amazonaws.com/4305_8df3611f69fa48c2ba6bbca9a8367895.html

Reference NO 6

http://egret.psychol.cam.ac.uk/statistics/R/graphs2.html

Reference NO 7

http://r4stats.com/examples/graphics-ggplot2/

Reference NO 8

http://learnr.wordpress.com/2009/06/01/ggplot2-positioning-of-barplot-category-labels/