A new indicator called “years 1820-2010″ has been added (you find it under “other”).
It is similar to the indicator “year 1950-“, i.e. it simply displays the year, with the only difference that this one covers a longer period. This is more suitable if you want to look at longer periods, e.g. air pollution and income. Use “year 1950-” when you want to look at a shorter time period.
By using this indicator for the color of the bubbles (which you do in the top right corner of the graph) and using “trails” for a selection of countries you can more easily compare the development over time of these countries.
Here you see an example of this (opens in a new window). In the graph you see a comparison of the development of both incomes and sulfur emissions of India, Malaysia and United Kingdom between 1860 and 2000. The blue and green bubbles show the situation in the second half of the 19th century and the red bubbles show the situation in late 20th century.
Here is a link to the spreadsheet of the indicator.