Low Exchange Rate

Why is the value of USD keeps on dropping? Everyone going for Euro dollar is it? Due to that, I am not getting much online income after conversion compared to many months ago. After so long of not withdrawing any USD from my paypal, I thought of withdrawing some to invest in gold coin. Upon seeing the exchange rate, I decided to wait a little longer hoping that the rate will go up higher. Unfortunately, it went down lower! So, I quickly withdraw some but still have not use the money to buy any gold yet because the gold price went up higher!