Downsizing Rims to Improve Fuel Economy ?

Here something I ran into. Maybe we need to consider a downsize at a time when our fuel prices continues to go up.

Car and Driver, a motoring magazine in the US conducted a test to figure out how much of a hit would fuel consumption take if the size of a car’s rims were increased or decreased. To make sure the rim size was the only variable, the tyre make was kept the same, tyre pressure was kept as recommended and tyre compounds were nearly identical. All tests were conducted using a standard Volkswagen Golf and all but the 15 inch rims, were aftermarket alloys.
The results of this test was as expected:
Rim Size (inches)/Overall weight (rim + tyre)/Fuel Consumption
19/24.5kg/(9km/L)
18/23kg/(9.3km/L)
17/22kg/(9.7km/L)
16/21kg/(9.74km/L)
15/18kg/(9.9km/L)

Read the full report on CarandDriver

If you have tried this, I would like to know your experience.