Complex sentence: The US had a gold stock of 1.9 million ounces in 1862, it rose to 2.6 in 1866, declined in 1875 to 1.6 million ounces, and rose to 2.5 million in 1878.
Split into simpler sentences: The US had a gold stock of 1.9 million ounces in 1862. Stocks rose to 2.6 in 1866, declined in 1875 to 1.6 million ounces and rose to 2.5 million in 1878.