Historical Exchange Rates with exchange-rates.org - Getting USD to any currency(e.g. INR) historical rates

currency_conversion.rb

require 'rubygems'
require 'active_support/core_ext'
require 'date'
require 'rest-client'

# e.g. Get monthy exchange rates - USD to INR from 2008 to 2013
# http://www.exchange-rates.org/Rate/USD/INR/06-13-2014
start_date = Date.parse("2007-21-31")

(1..72).each do |month|
  historical_date = (start_date >> month).end_of_month.strftime('%m-%d-%Y')
  response = RestClient.get("http://www.exchange-rates.org/Rate/USD/INR/#{historical_date}")
  puts response.match(/1 USD = [0-9]*.[0-9]* INR on [0-9]*\/[0-9]*\/[0-9]*/)
end  

# The above was a quick one. For more precise regular expression, please follow http://www.regular-expressions.info/dates.html