Advice on Using International Futures Historical Data:
How to smooth a trend line that "jumps" around from year to year:

When using the extensive historical data contained in the International Futures databases, it is important to note the extensiveness of coverage – especially when examining the "World" or "Groups" of nations.  You can do this by looking at the "Data Information" tab when selecting a variable for analysis.  "Data Information" will till you the various sources for the data and  the "Year by Year Availability" of the data.  If data is only available from 20% of the World's countries for certain years and from 95% of the World's countries for other years then the "trend" graph might look very "ragged"  The "ups and downs" are not "real" ones, but are due to great variation in coverage.  The easiest way to uncover the "real" trend would be to plot only those years for which the coverage is extensive. 

Here is an example of this "problem" and the solution:  The World's TFR (Total Fertility Rate, or average # of children per woman) using all years for which data is available:

Notice that this "trend" is very irregular.  From year to year the World's TFR seems to be dropping dramatically and then shooting back up again.  When you examine the "Year by Year" availability of data, the source of this irregularity becomes clear:  Data is available from 88% to 96% of all countries for years ending with 0s and 5s, but it is only available from 20% of countries for years ending in 1s, 3s and 4s; these "20% countries" are happen to be more developed countries with low TFRs.  The solution is to "right click" on the graph and choose "Customization Dialogue."  Go to "Points," click on "Selected" and then just choose the years with high data availability -- 1960, 1965, 1970, etc... (hold down the "Ctrl" key and click on the years you want).  Now the the World's TFR trend is much more accurate: