# Data choices — ev-market-vs-tesla story **Searched.** For the market: the IEA Global EV Data Explorer (blocked, HTTP 403; also non-CC terms, see PROVENANCE.md), Our World in Data's republication of it (used in the first draft, dropped after the fact check because its licence is not established), and the text of the IEA's *Global EV Outlook 2026* report (CC BY 4.0, used). For Tesla: DataPressr's `tesla-quarterly-deliveries` dataset (reused, pinned to a commit) plus the one newer release. **Chose the report's own stated figures.** They are openly licensed and are the IEA's headline numbers, but they are rounded and often bounded ("more than 20 million", "less than 20%", "around 1.5 million"). The story keeps the qualifier in every chart label and sentence, draws bars for bounded figures at the stated value, and computes nothing more precise than the inputs support. This rules out a continuous 2020–2025 market series and the earlier draft's 2023-to-2025 comparisons (e.g. Tesla's share of battery-electric sales by year), which needed the data product. **Definitions, and why they matter here.** - *Electric cars* in the IEA report are new passenger cars sold that are battery-electric (BEV) or plug-in hybrid (PHEV); "sales" means new vehicles hitting the road, from registrations where possible (p. 16, footnote 2). Tesla makes only battery-electric cars, so the fair denominator for Tesla's share is battery-electric sales. - *Battery-electric sales, 2025* are not stated as a count. 65% of "more than 20 million" is about 13 million; because 65% is rounded, `calculate.mjs` uses 64.5% for a lower bound (12.9 million), which puts Tesla's 1,636,129 deliveries at no more than 12.7% of battery-electric sales, reported as "less than 13%". The 12.9 million BEV lower bound assumes the reported 65% was rounded to the nearest percentage point; the resulting 'less than 13%' comparison is conditional on that assumption. Tesla's deliveries exceeded US electric car sales ("around 1.5 million") by approximately 0.14 million; this comparison is not used in the post. - *Tesla deliveries* are vehicles handed to customers worldwide, counted by Tesla; Tesla's release says its figures "represent passenger vehicles sold to customers". The IEA's own figure for Tesla's battery-electric sales in 2025 is 1.6 million, down 9% (p. 217), consistent with Tesla's 1.64 million deliveries, down 8.6%. We do not adjust either. - *Annual Tesla figures* are the full-year recaps in each Q4 release. For 2023–2025, `calculate.mjs` checks that the four quarters as first reported sum exactly to the recap (they do; for 2020 and 2021 they do not, see the dataset README). **Regions.** "Outside China, Europe and the United States" is the IEA's own grouping in the report text (p. 23). **Licence and required disclaimer.** The report figures are used under CC BY 4.0 (), subject to the IEA's [Notice for CC-licensed Content](https://www.iea.org/terms/creative-commons-cc-licenses). Attribution: IEA (2026), Global EV Outlook 2026, https://www.iea.org/reports/global-ev-outlook-2026, Licence: CC BY 4.0. As the notice requires for adaptations: "This is a work derived by Datopian (DataHub) from IEA material and Datopian (DataHub) is solely liable and responsible for this derived work. The derived work is not endorsed by the IEA or its Member countries in any manner." **What the data cannot say.** It does not give Tesla's deliveries by country, so Tesla's share within China, Europe or the US cannot be computed. It does not give any other carmaker's sales; the BYD comparison is the IEA's statement, quoted. The IEA figures used here end in 2025 and include no January–September 2026 total comparable with Tesla's (the report does give global sales for Q1 2026, around 3.9 million, down 8%, and a forecast for the year), so the 2026 comparison is Tesla against its own past.