Owning an iPhone or iPad is the best indicator of wealth in the United States, according to a new National Bureau of Economic Research working paper by economists from the University of Chicago.

In 1992, the strongest sign of a rich family was if they used Grey Poupon mustard, while in 2004, it was Land O' Lakes butter and Kikkoman soy sauce. In 2016, it was owning an iPhone or iPad, a trend that will likely continue into the future with the iPhone X and the smartphone's upcoming models.

If You Own An iPhone, You're Likely Rich

"Across all years in our data, no individual brand is as predictive of being high-income as owning an Apple iPhone in 2016," researchers Marianne Bertrand and Emir Kamenica wrote.

The study utilized data from Mediamark Research Intelligence, with a sample size of 6,394 people. The data included bi-annual questionnaires and information obtained from face-to-face interviews such as household income.

According to the researchers, owning an iPhone gave them a 69.1 percent chance of correctly guessing that a person was in the high-income bracket, or top quartile, of his or her group, such as single adults or couples with dependents. Meanwhile, owning an iPad has a slightly lower success rate, at 66.9 percent.

For 2016, other significant indicators of wealth include subscribing to Verizon at 61 percent and owning a generic Android phone at 59.5 percent.

Meanwhile, in terms of products, the best indicator of wealth in 2016 was traveling in the continental United States at 70.9 percent and owning a passport at 70.3 percent. These signs are a far cry from the top products of previous years. In 1992, it was owning an automatic dishwasher at 71.4 percent and using dishwater detergent at 70.2 percent. In 2004, it was buying a new vehicle at 73.6 percent and, again, using dishwater detergent at 71.6 percent.

The Future Of The iPhone

The study took a look at 2016 data, but the result of owning iPhones and iPads being the best indicator that a person is rich may continue into the succeeding years.

This year, Apple is reportedly looking to launch three iPhone models. Two of the 2018 iPhones, the 5.8-inch OLED iPhone and the 6.5-inch OLED iPhone, are expected to follow, and possibly even exceed the $1,000 price point of the current iPhone X.

Apple, however, is reportedly looking to release a budget iPhone model compared to the OLED iPhones. The 6.1-inch LCD iPhone is said to be priced at $700, and it remains to be seen whether owning it will still be a sign of being a rich person.