While there's no truly objective way to determine which Pokémon movie is the most popular, I thought I could potentially gain some insights by monitoring the order of results for Pokémon movies on the US store. Each day for a 10-day period from 8/22 to 8/31, I did a search for "Pokemon" on the US iTunes store, and noted the rankings:
| Movie | Average Rank | Standard Deviation |
| Pokémon: Detective Pikachu | 1 | 0 |
| Pokémon: The First Movie | 2 | 0 |
| 3-movie pack (Detective Pkachu/Small Foot/Lego Movie 2) | 3.2 | 0.422 |
| Pokémon 2000: The Power of One | 3.8 | 0.422 |
| Pokémon: Lucario and the Mystery of Mew | 5 | 0 |
| Pokémon 3 | 6.4 | 0.516 |
| Pokémon: Hoopa and the Clash of Ages | 6.9 | 0.734 |
| Pokémon: Arceus and the Jewel of Life | 8.1 | 1.101 |
| Pokémon: I Choose You! | 9.4 | 1.506 |
| Pokémon: The Rise of Darkrai | 10.7 | 1.337 |
| Pokémon: Genesect and the Legend Awakened | 11.3 | 1.059 |
| Pokémon Ranger and the Temple of the Sea | 12.1 | 1.287 |
| Pokémon: Giratina and the Sky Warrior | 12.3 | 3.653 |
| Pokémon: Zoroark: Ruler of Illusions | 14.3 | 0.675 |
| Pokémon: Kyurem and the Swords of Justice | 14.8 | 1.229 |
| Pokémon: Diance and the Cocoon of Destruction | 16 | 0.816 |
| Pokémon the Movie White: Victini and Zekrom | 16.4 | 1.265 |
| Pokémon: The Power of Us | 17.6 | 0.699 |
| Pokémon: Volcanion and the Mechanical Marvel | 18.8 | 0.789 |
| Pokémon the Movie Black: Victini and Reshiram | 19.9 | 0.316 |
| Pokémon: Mewtwo Strikes Back Evolution | 21 | 0 |
Raw Data
Average Rank: The title's average position across all ten days. Lower numbers appeared earlier.
Standard Deviation: Average variance in rank over the 10-day period. Higher numbers indicate greater variability in rank.
Notes:
Notes:
-Movies four through seven (originally distributed by Miramax) are not currently available on iTunes US and therefore are not ranked.
-Each day's ranking was obtained by searching "Pokemon" on the US iTunes store on my iPhone between 11am and 1pm Central time.
-Based on my long-term observations, search ranking appears to be a function of relevancy and sales. There's no guarantee that all the movies are considered equally relevant.
Observations and theories on specific movies:
Pokémon Detective Pikachu: Unsurprising that the movie with by far the highest box office gross would rank the highest.
Pokémon: The First Movie: Also not surprising given the cultural status of this film.
3-movie pack/Pokémon 2000: These have a tendency to swap places.
Pokémon: Lucario and the Mystery of Mew: Likely benefits from being well-loved by fans, and also being the last 4Kids-produced movie.
Pokémon: Hoopa and the Clash of Ages: Somewhat surprisingly high given the general reputation of the XY-generation movies. It may have benefited from Hoopa-related events in Pokémon Go, but I honestly think Hoopa is one of the more popular Pokémon from that era, and the podcast episode discussing that movie's music is reasonably popular.
Pokémon the Movie Black/White: Obviously at a disadvantage since a large number of consumers will buy just one instead of both. I did find it interesting that "Zekrom" consistently ranked above "Reshiram". Perhaps it benefited from the limited theatrical showing in the US.
Pokémon: The Power of Us: Rather surprising (and disappointing) to see this well-regarded film so close to the bottom. I have heard that it grossed significantly less than "I Choose You!", probably due to having less of a "hook". I still maintain that they should have at least used the more recognizable western version of Lugia's theme in the score, if possible.
Pokémon: Mewtwo Strikes Back Evolution: While it obviously has the (sales) disadvantage of being easily available on and closely associated with Netflix, seeing it consistently at the bottom of the list suggests that despite its popularity on the service, much of the public doesn't feel compelled to purchase it, at least digitally.
