Among the countries with population of more than 50 million, Great Britain finished first, winning medals disproportionate to its population. The average country in this list got one medal for every 8 million citizens; Britain got 8X that.
Among the countries with GDP of more than $1 trillion, Great Britain finished second, making more of its money than anyone save Russia, with its great tradition of Olympic champions. The average country in this list generates about $84 billion in GDP for each Olympic medal. Great Britain spent only $38 billion, considerably more than Russia's $23 billion but still getting more than twice as many medals per dollar than the average country in this list of 15.