Here is a simple, Jain-documents-based view of Jain population over the last century or so.

• Early 20th century (around 1890s–1920s): Contemporary sources note a Jain population in India around 1.0 to 1.4 million, with figures like about 1.417 million in 1891 and about 1.179 million in 1921. These numbers come from historical Jain demographic discussions and temple histories of that era. This shows Jains were a significant minority but still a relatively small community. ( en.wikipedia.org, jainknowledge.com)

• 2000s to 2010s: The Indian Census (latest widely cited in public sources) shows Indian Jains around 4.2–4.5 million in 2011, making up roughly 0.4% of India's population. This period marks a clear growth from the earlier century, reflecting population growth and continued Jain communities across major states. ( ceicdata.com, en.wikipedia.org)

• 2010s to present: In 2014, the Jain community was officially designated as a national minority in India, reflecting its recognized demographic presence, though precise total numbers continue to be cited primarily from the 2011 census data (about 4.4–4.5 million in India). Globally, Jain populations are concentrated in India with smaller communities in North America, Europe, East Africa, and elsewhere, but exact global counts are not as systematically documented as India’s census. ( en.wikipedia.org)

• Key note for today: Most reliable recent public estimates place Indian Jains at about 4.4–4.5 million as of 2011; India remains the heartland of Jain demography, with smaller communities abroad. Population figures beyond India are less precisely tracked in common sources.

If you’d like, I can point you to specific Jain Knowledge pages that discuss Jain history and demography in more detail.