A new study conducted by Apptopia analyzed the top 50 Apple App Store games in the US using data gathered from 2014 to 2017. The results paint a stark picture of the gaming app market, with the top 50 games taking in 76 percent of the total revenue, leaving all others to fight over the remaining 24 percent.

On average, the top 50 grossing games retain their positions for 27.7 days, and in those years, only 14 games from 10 publishers managed to take the number one spot, and an elite three—Supercell, Machine Zone and Bandai Namco—had multiple number one games.

About two-thirds of the games studied dropped off the list within five days, with a third of titles lasting a single day. Only six games stayed among the top 50 throughout all the years studied: Game of War: Fire Age, DoubleDown Casino Slots & More, Big Fish Casino: Slots & Games, Slotomania Slots: Vegas Casino, Candy Crush Saga and Clash of Clans. The three top genres among the 25 games with the longest consecutive streaks on the top 50 list are casino and puzzle, with a four-way tie between arcade, role-playing, simulation and strategy.

“Since we’re talking money, it’s no surprise that three of these are casino games,” wrote Apptopia.

Meanwhile, non-casino titles such as Game of War: Fire Age invested $40 million into a massive advertising blitz in 2014, with Kate Upton becoming the chief spokesmodel who starred in the famously risqué Superbowl XLIX trailer and helped propel the game to the top of the charts. In comparison, Candy Crush Saga began its rise by focusing heavily on social media, as it was originally launched as a Facebook game that quickly caught on. Developer King continually engaged with that user base, which included about 1 in 23 Facebook users in 2017, who in turn spread the word and invited others to play when Candy Crush Saga launched on mobile devices.

Although it’s hard to believe, Clash of Clans had a slightly slower start, and developer Supercell couldn’t afford to spend much on marketing when it launched. The developer had to rely heavily on free marketing and some degree of luck while constantly improving the game, particularly when Apple’s editorial team chose it to be a featured game on the App Store. Having it be fun, addictive and unique helped a lot, but the fact that the game helped highlight key features like retina screens probably made it more attractive, too. Supercell then used the influx of money to invest heavily in marketing, particularly through ads on Facebook where Supercell could filter its audience to target gamers of specific age ranges and income levels. Clans also had a Super Bowl ad that played alongside Game of War‘s, and now the game brings in more than $5 million a day in revenue.

Ranking among the top 50 is no small feat, and staying there is even more difficult, and doing so means tremendous rewards. Over 800,000 games were listed on the App Store during the multi-year period, and 2,624 of them reached the top 50. Of those games, 119 stayed in the top 50 for over 100 days, 38 remained for over 500 days, and only 15 managed to stay on for over 1,000 days. The few games that managed to stay on the list for longer than a month saw considerable returns, with in-app purchases totaling around $750,000 per day for top five games, while top 10 games brought in about $340,000.

The study only measures in-app purchases and does not take into account potential advertising revenue. However, Apptopia notes that all the top grossing games have something in common: balance between player gender.

“The top grossing mobile games got there because they understand how to incorporate game mechanics and themes that people of all ages and sexes can enjoy,” wrote Apptopia COO Jonathan Kay in a blog post. “While identifying a niche can be lucrative, the serious money is made by catering across demographics.”

But the good news is that, depending on the size of your company, being ranked outside of the top 50 can still be quite lucrative. Mobile gaming continues to grow, with data from MediaKix showing that the number of active mobile gamers has grown to 2.1 billion worldwide, totaling over $50 billion in revenue, which is expected to hit $72 billion by 2020. Games also comprised about 80 percent of all app revenue in 2017.