Even US laws explicitly refer to SI, for example the Metric Conversion Act of 1975: http://www.gpo.gov/fdsys/pkg/STATUTE-89/pdf/STATUTE-89-Pg100...
The question of GGP was, whether some countries use other metric systems which are not SI. I don't think such a country exists.
At about the same time as the Imperial unit reform Britain introduced the "florin" 2 shilling coin, 10 per pound, another vague attempt at decimalization.
>In 1981, the USMB reported to Congress that it lacked the clear Congressional mandate necessary to bring about national conversion. Because of this ineffectiveness and an effort of the Reagan administration — particularly from Lyn Nofziger's efforts (http://www.washingtonpost.com/wp-dyn/content/article/2006/03... ) as a White House advisor to the Reagan administration, to reduce federal spending — the USMB was disbanded in the autumn of 1982.
>The metrification assessment board existed from 1975 to 1982, ending when President Ronald Reagan abolished it, largely on the recommendation of Frank Mankiewicz and Lyn Nofziger. Overall, it made little impact on implementing the metric system in the United States.
>According to Mankiewicz, he prompted Lyn Nofziger's efforts to halt the 1970s U.S. metrication effort, who convinced President Ronald Reagan to shut down the United States Metric Board
> So, during that first year of Reagan's presidency, I sent Lyn another copy of a column I had written a few years before, attacking and satirizing the attempt by some organized do-gooders to inflict the metric system on Americans, a view of mine Lyn had enthusiastically endorsed. So, in 1981, when I reminded him that a commission actually existed to further the adoption of the metric system and the damage we both felt this could wreak on our country, Lyn went to work with material provided by each of us. He was able, he told me, to prevail on the president to dissolve the commission and make sure that, at least in the Reagan presidency, there would be no further effort to sell metric.
>It was a signal victory, but one which we recognized would have to be shared only between the two of us, lest public opinion once again began to head toward metrification.
And Fahrenheit's higher unit precision is a distinct advantage in taking and interpreting temperatures of people, particularly children.
Faherenheit's 0-100 range is basically a close match for the extremes in weather temperature experienced by typical human beings. Celsius is not even close. Additionally, Fahrenheit's scale has roughly twice the resolution of Celsius, and humans are good at distinguishing this precision. Unit precision is also helpful for body temperature.
Regarding the distant secondary use: obviously Celsius's range matches freezing and boiling: but because water's phase change is consistent and obvious at these temperatures (modulo altitude), cooking rarely involves measuring temperatures in this range except for unusual cases like candy. Celsius has no advantage at all for the primary use of temperature in cooking: baking.