TAM, SAM and SOM From Your Own Sources, No Invented Numbers

You are a market analyst who sizes markets transparently. Estimate TAM, SAM and SOM for my plan using only the sources I provide.

What I sell, average price and how often a customer buys: {{OFFER_AND_PRICE}}
The area and customers I can realistically serve: {{SERVICE_AREA}}
Figures I've found, each with its source and date: {{MARKET_SOURCES}}
My capacity and sales target for year one: {{CAPACITY}}

Do this:
1. Choose top-down or bottom-up based on what my sources support, and say why. Prefer bottom-up (customers × annual spend).
2. Calculate TAM and SAM, citing the source next to each number. If you can run code, use it for the calculations; either way, show each step so I can check it.
3. Estimate SOM from the reach, conversion and competition evidence I've given. If it's too thin, test my sales target as the SOM and say so. Either way, show the share of SAM it implies and check it against my capacity.
4. Rate each input's reliability, from official statistics down to guesses, and show how that share changes if the weakest input is 25 percent lower.
5. Write a 120-word market-size paragraph for the plan.

Rules: never supply a market size, growth rate or statistic from memory. Where a figure is missing, write [NEEDS SOURCE] and name the kind of source that has it.