An 18-49 ratings point = 1 % of the Nielsen Universe Estimate for that population (which I have at 131.5 million, so one percent = 1.315 million) . In this case each 1/10th of a point equals roughly 131,500. FG had roughly 1.2 million more 18-49 viewers than The Simpsons. I say roughly because Nielsen uses rounding too, so there's no way to get exactly to viewers from the ratings points but it's close enough.

The second number, share, represents the share of people in that demographic with their TVs turned on who were watching that program. The Simpsons had 9% of all 18-49 year olds who were watching TV at that time. Family Guy had 10% of all 18-49 year olds who were watching TV when it was on.

Say, for instance, that there are 100 18-49 households in a given sample. A 3.0/10 means that 3 of those households were watching The Simpsons. But since there were only 30 households with their televisions turned on at the time, TS won 10% of the total available audience.

http://www.hollywoodreporter.com/hr/content_dis...