Unit rates and unit ratios. A unit rate is a ratio that has a denominator of 1. A unit rate is also called a unit ratio. (They mean the same thing.). $\frac{5}{4}$ and $3:8$ and $40\mbox{ to }10$ are ratios, but they are not unit ratios. $\frac{1.25}{1}$ and $0.375:1$ and $4\mbox{ to }1$ are unit ratios. unit rate is also called a unit ratio. (They mean the same thing.). $\frac{5}{4}$ and $3:8$ and $40\mbox{ to }10$ are ratios, but they are not unit ratios.
I found the following references to Coca-Cola Zero launching in the US in 2005: 1  Associated Press March 21, 2005 announcement that the product would launch in June - http://www.nbcnews.com/id/725792...  Case study by ATTIK, which provided worldwide branding services, citing a 2005 launch - ATTIK.
It was part of the 7 Up family of soft drinks, and was introduced in September 2002. It was launched in the same year as other attempts to extend soft drink brand names with new variations, including Pepsi Blue, Dr Pepper Red Fusion and Vanilla Coke.