Between 90% and 96% of wildfires are of human origin, caused by human activity.

Omissions

• The two most commonly cited official figures are 95% (European Commission and EEA) and 96% (EEA, EU-specific), so the speaker's lower bound of '90%' is slightly below the official range, while the upper bound of 96% matches the EEA figure.
• The official sources generally refer to Europe or the EU as a whole; the exact share varies by country and year (in some southern European countries, lightning accounts for a small but non-negligible share).
• Publication dates of the cited official pages could not be firmly established from the search results.

Sources

• PrimaryEU Civil Protection Knowledge Network (European Commission) — Forest fires / WildfiresIt is estimated that 95 % of wildfires in Europe are directly or indirectly caused by human behaviour and activities, including negligence and accidents.
• PrimaryClimate-ADAPT (European Environment Agency) — Exposure to burnt areasIn Europe, it is estimated that 95% of wildfires are caused directly or indirectly by human activities, increasingly ...
• SecondaryEuractiv — From arson to carelessness: how humans set Europe on fireThe European Environment Agency supports this view, estimating that 96% of wildfires in the EU are caused by human activity.