With so much speculation over the past several years about whether the Federal Reserve will raise interest rates, it is easy to forget how unusual a rate increase is — and not just for the Fed, but for any major central bank. Aside from three small U.S. rate hikes, other major central banks have made 23 rate changes since 2013 – all cuts. As expected, the Fed raised rates at its March meeting, but investors may be wondering how long it will be before other central banks follow suit.