<P> The metric system has been officially sanctioned for use in the United States since 1866, but the U.S. remains the only industrialised country that has not fully adopted the metric system as its official system of measurement, although in 1988 the United States Congress passed the Omnibus Foreign Trade and Competitiveness Act, which designates "the metric system of measurement as the preferred system of weights and measures for U.S. trade and commerce". Among many other things, the act requires federal agencies to use metric measurements in nearly all of its activities, although there are still some exceptions allowing traditional linear units to be used in documents intended for consumers . Many sources also cite the countries of Liberia and Myanmar (Burma) as the only other countries not to have done so . Although the United Kingdom also uses the metric system for most administrative and trade purposes, imperial units are widely used by the public and are permitted or obligatory for some purposes, such as road signs . </P> <P> Although the originators intended to devise a system that was equally accessible to all, it proved necessary to use prototype units in the custody of national or local authorities as standards . Control of the prototype units of measure was maintained by the later French governments until 1875, when it was passed to an international intergovernmental organisation, the General Conference on Weights and Measures (CGPM). </P> <P> From its beginning, the main features of the metric system were the standard set of interrelated base units and a standard set of prefixes in powers of ten . These base units are used to derive larger and smaller units that could replace a huge number of other units of measure in existence . Although the system was first developed for commercial use, the development of coherent units of measure made it particularly suitable for science and engineering . </P> <P> The uncoordinated use of the metric system by different scientific and engineering disciplines, particularly in the late 19th century, resulted in different choices of base units even though all were based on the same definitions of the units of the metre and the kilogram . During the 20th century, efforts were made to rationalise these units, and in 1960, the CGPM published the International System of Units, which has since then been the internationally recognised standard metric system . </P>

Measurement system whose divisions are powers of ten