Intergalactic Summit

Could the 2% apply to citizens that are goung through the process of being fully indoctrinated into the faith? For instance, children who have yet to complete all necessary rituals?

The Amarr Empire, consisting of the Aridia, Bleak Lands, Devoid, Domain, Genesis, Kador, Kor-Azor, and Tash-Murkon regions, contains 152 space stations which belong to Big 8 Megacorporations, broken down as follows:

CBD Corporation - 42 stations (Nearly half their total stations, and more than they have in State space)
Aridia: 12 stations
Kador: 6 stations
Kor-Azor: 6 stations
Tash-Murkon: 12 stations
The Bleak Lands: 6 stations

Ishukone Corporation - 20 stations
Domain: 8 stations
Kor-Azor: 4 stations
Tash-Murkon: 8 stations

Kaalakiota Corporation - 54 stations
Aridia: 6 stations
Devoid: 6 stations
Domain: 6 stations
Genesis: 6 stations
Kador: 18 stations
Tash-Murkon: 12 stations

Nugoeihuvi Corporation - 16 stations
Kor-Azor: 12 stations
Tash-Murkon: 4 stations

Wiyrkomi Corporation - 20 stations
Aridia: 8 stations
Genesis: 4 stations
Kador: 4 stations
The Bleak Lands: 4 stations

Two other notable Caldari corporations have stations in the Amarr Empire:

Expert Distribution - 36 stations
Modern Finances - 4 stations

That's a total of 192 stations. Every Caldari aboard those stations is a corporate citizen in the Empire, working on a Caldari jobsite on Caldari work visas.

I should point out that's just the space-side information I have access to. Corporations such as Caldari Constructions, Expert Housing and Echelon Entertainment will all also have countless dirtside corporate enclaves and the Okusaiken will have arcologies to meet the work contract demands of an Empire hungry for high-tech Caldari goods and high-quality Caldari work. I'm aware of at least one Zainou lab in Hedion, co-operating with the Empire's experts in cybernetics and anti-agatics.

Again, every one of the Caldari living and working within those enclaves will also be a corporate citizen outside of the usual slave-commoner-holder hierarchy. That accounts for most of the three trillion.

The remainder will, yes, be ethnic Caldari who converted to Amarr and became citizens of the Empire. And I daresay a fair few of the corporate workers will be Amarr convertees too - it's a religion built around proselytization and conversion after all, it seems entirely likely that it would succeed occasionally. Especially among Caldari who already have the Maker as a springboard into monotheism and no particular reason to hate or distrust the Amarr.

But no, most of those three trillion are not Imperial citizens, they're State citizens who happen to be permanently living and working in the Empire.

This was initially surprising to me but on reflection I guess it makes sense - CBD are an import/export corporation.