Silver often tracks the gold price due to store of value demands, although the ratio can vary. The gold/silver ratio is often analyzed by traders, investors and buyers. In Roman times, the ratio was set at one to 12 or 12.5. In 1792, the gold/silver ratio was fixed by law in the United States at 1:15, which meant that one troy ounce of gold would buy 15 troy ounces of silver; a ratio of 1:15.5 was enacted in France in 1803.
The average gold/silver ratio during the 20th century, however, was 1:47. The lower the ratio/number, the more expensive silver is compared to gold. Conversely the higher the ratio/number, the cheaper silver is compared to gold.
[Source: Wikipedia]