In fact, it's been a long time coming, as Singapore has consistently waffled back and forth in the rankings year-over-year, ascending to fourth in 2015, and falling back to fifth last year.
As for the rest of the top 10, the results more or less showcase some familiar countries, with the rest listed below in descending order:
10. Slovenia, Slovakia, Poland, Lithuania, Latvia: 149
9. Hungary: 150
8. Malta, Czech Republic, Iceland: 152
7. Australia, Greece, New Zealand: 153
6. Malaysia, Ireland, Canada, United States: 154
5. Luxembourg, Switzerland, Netherlands, Belgium, Austria, Portugal: 155
4. Denmark, Finland, Italy, France, Spain, Norway, Japan, United Kingdom: 156
3. Sweden, South Korea: 157
2. Germany: 158
1. Singapore: 159
While the news is pretty good for most countries belonging to the European Union, it'd probably be wise to look into renewing your American passport quickly. Domestic travel to some US states might require passports pretty soon, in a move that would sure to make any Singaporean laugh in your face.