Change Over Time
Here's a nice way to show change over time. The ruler is from series Tools 011, which illustrates a qualitative change. The Q1 2011 marker is under the animated 2012 marker, which is animated to move either right or left on the value scale. The arrows that show the direction of movement are important. If you don't use the arrows, you'd need to add a legend, which is less desirable. Download the animation example to see how this has been formatted. The arrow is animated with an entrance wipe from the appropriate direction (from left or from right), depending on the direction of the 2012 marker motion path. The marker and the arrow for each topic are formatted to both animate at the same time and ad the same speed. You will need to adjust the length of the arrows so that they span the empty space between 2011 and 2012 (for example).
If you want, you can add more years. Say you wanted to add 2013 when you have data available. You can add another marker in another color and animated it to 1) appear directly under the 2012 marker and then 2) move right or left to the value desired. Add arrows from 2012 to 2013: color of the arrow should be same as 2013 marker and wipe direction set to match the movement direction of the 2013 marker. And so on. You may want to place the 2012-2013 arrows slightly lower than the 2011-2012 arrows so they appear distinct (not on top of each other). Enjoy using this chart.