Function getTaxRateByState

getTaxRateByState(state: string): undefined | number
Gets the sales tax rate for a given US state code.
Parameters
- state: string
  The 2-letter state abbreviation (e.g., 'CA', 'TX').
Returns undefined | number
The sales tax rate as a percentage, or undefined if not found.
Example
```
const rate = getTaxRateByState("TX");
console.log(rate); // Output: 6.25 (if defined in stateTaxRates)
```
- Defined in src/currency/utils.ts:40