Americans aren't as happy as they used to be. Win McNamee/Getty Images Happiness has been regarded an unalienable American right from the very moment the nation formed.

Yet, American happiness has fallen over the past decade, according to the 2017 World Happiness Report, an annual ranking by the United Nation's Sustainable Development Solutions Network.

The report ranks 155 countries to find how happy their lives are using a scale of 0-10 on a number of metrics, such as gross domestic product (GDP) per capita, freedom to make life choices, generosity, and perceptions of corruption.

The US came in at number 14 overall in the ranking in 2017, down one from the previous year. It has never cracked the top 10.

A recent decline in happiness appears even starker when looking to the results of a measure where Americans are asked to envision where they fall on a ladder that rates their "best possible life."

Americans were first asked that question in 2006, and in 2007 the US had the third-highest happiness results of 23 OECD countries. Today, that response is at its lowest point yet, ranking 19th of 34 OECD countries.

"America's crisis is, in short, a social crisis, not an economic crisis,"economist and Columbia University professor Jeffrey D. Sach wrote in a chapter of the report called "Restoring American Happiness."

Sachs mentions that while per capita GDP — an indicator used to gauge the economic health of a country — is rising, happiness is falling.

"The United States can and should raise happiness by addressing America's multi-faceted social crisis—rising inequality, corruption, isolation, and distrust—rather than focusing exclusively or even mainly on economic growth, especially since the concrete proposals along these lines would exacerbate rather than ameliorate the deepening social crisis," he wrote.

Social capital has been on the decline for decades, according to the report, which counts soaring income inequality, economic and ethnic segregation, and deterioration in America's educational system among the causes.

Rather than attempting to raise economic growth, the report points the US to the Nordic countries of Denmark, Finland, Iceland, Norway, and Sweden, which all rank in the top 10, even though the countries all have lower GDP per capita than the US.