Add comprehensive SNAP utility allowance data (FY2019-FY2026, sub-regions, household size)

[MaxGhenis]

Summary

Ref #7741, ref #7721

New data

• Add FY2018, FY2019, FY2020, FY2021, FY2023, and FY2026 SNAP utility allowance values for all 53 states/territories
• FY2018–FY2021 covers all allowance types: HCSUA (standard), LUA (limited), and all 6 individual utility allowances (electricity, gas/fuel, phone, sewage, trash, water)
• Total coverage is now FY2018–FY2026 (continuous from 2017-10-01)
• Split Alaska into 6 SNAP utility sub-regions (Central, Northern, Northwest, Southcentral, Southeast, Southwest) per 7 AAC 45.531, with county-to-region mapping
• Split New York into 3 sub-regions (Nassau/Suffolk, NYC, Other NY) with county mapping
• Add household-size-based SUA and BUA for AZ, TN, VA (NC was already modeled)
• Add HI and GU individual utility allowances (electricity, gas, water) that vary by household size
• Rename participating_states → states parameter files for clarity

Bug fixes

• Fix 6 FY2019 SUA values per SNAP QC Technical Documentation Table F.7: MN HCSUA (556→493), CO LUA (304→354), AR phone (50→25), MN phone (41→47), NE phone (46→48), NH phone (28→29)
• Fix FY2019 GA phone (47→41) and AK_SE phone (29→28) per SNAP QC Tech Doc
• Fix Maryland SUA/LUA effective dates from October 1 to January 1 (Maryland uses calendar-year cycle, not federal fiscal year); corrected 2023 SUA value from $551 to $505; corrected 2019-01-01 values (HCSUA 420→404, LUA 257→247); added missing 2020 and 2025 entries
• Fix Indiana SUA values and effective dates per IN DFR policy transmittals
• Fix Alaska region values and date entries; fix 23 AK individual utility FY2018 values
• Fix Wyoming YAML formatting
• Fix HI trash FY2018 (0→88), WV electricity FY2021 (78→76)
• Add NH FY2021 mid-year correction (HCSUA 701→702, LUA 256→257, effective June 2021)
• Add 14 missing FY2018 individual utility entries (AZ phone, DE 5 utils, IN 5 utils, MD phone, NH electricity, WI sewage)
• Fix missing FY2019 LUA and individual utility allowance entries for all states (were only added to HCSUA); update LUA test expectation for CA 2021 (432 → 1602, now correctly reflects FY2019 CA LUA of $130)
• Add household-size floor guard (max_(1, min_(10, size))) in snap_standard_utility_allowance, snap_limited_utility_allowance, and snap_individual_utility_allowance to prevent ParameterNotFoundError when spm_unit_size is 0
• Fix FY2026 LUA/IUA data swap for 10 states/regions (AR, IA, LA, MA, OK, TX, UT, NY_NAS, NY_NYC, NY_ONY) — bogus LUA values were placed in IUA fields and LUA values were zeroed out
• Fix by_household_size/states.yaml effective date from 2024-01-01 to 2023-10-01 to match amount data (AZ/TN had household-size-varying SUA since at least FY2019 per USDA spreadsheets)
• Fix SNAPUttilityAllowanceType typo → SNAPUtilityAllowanceType

Cleanup

• Remove unit: USD from boolean parameter files (states.yaml, active.yaml, etc.)
• Fix name: → title: in parameter reference metadata
• Apply underscore formatting to numeric values across all parameter files
• Add FY2019 USDA SUA spreadsheet reference to all 8 parameter files
• Add missing reference: section to limited/active.yaml
• Refactor AK/NY county-to-region mappings to dict comprehensions

Related issues

• Backdate SNAP SUA (Standard Utility Allowance) values pre-FY2022 #7721 — Backdate SNAP SUA values pre-FY2022 (this PR resolves the binding constraint)
• Backdate SNAP utility allowances for FY2020-FY2021 (all states) #7741 — Backdate SNAP utility allowances for FY2020-FY2021 (now included)
• Add missing Alaska boroughs to county_enum.py (Haines, Petersburg) #7744 — Missing AK boroughs (Haines, Petersburg) in county_enum.py
• Track OBBBA "Heat and Eat" HCSUA eligibility change for FY2026 #7745 — OBBBA "Heat and Eat" HCSUA eligibility change starting FY2026

Data sources

• USDA SNAP utility allowance spreadsheets (including SNAP-SUA-Table-FY2019.xlsx via Wayback Machine)
• SNAP QC Technical Documentation (FY2018, FY2019, FY2020, FY2021) — Table F.7: Standard utility allowances
• snapscreener.com

Test plan

• All existing SNAP tests pass
• 11 new region/sub-region tests (AK sub-regions, NY sub-regions, HI/GU household-size IUA)
• AK Anchorage end-to-end integration test (county → region → SUA amount)
• Wrong-allowance-type-returns-zero tests for SUA and LUA
• Household size zero edge case test (verifies floor guard)
• FY2019 values verified against SNAP QC Tech Doc Table F.7 (6 corrections applied)
• FY2018/FY2020/FY2021 values verified against SNAP QC Tech Doc Table F.7
• CI passes

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.74%. Comparing base (9ddf56e) to head (bc30ab8).
⚠️ Report is 69 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##              main    #7726      +/-   ##
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- Coverage   100.00%   96.74%   -3.26%     
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  Files            2        7       +5     
  Lines           25      215     +190     
  Branches         0        6       +6     
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+ Hits            25      208     +183     
- Misses           0        7       +7     

Flag	Coverage Δ
unittests	96.74% <100.00%> (-3.26%)	⬇️

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[MaxGhenis]

Microsim impact analysis

Ran household-level examples comparing 2024 vs 2026 values — all features working correctly:

SUA examples:

State	2024 SUA	2026 SUA	Change
CA	$7,299	$7,956	+$657 (+9.0%)
NC HH3 (by HH size)	$8,607	$9,216	+$609 (+7.1%)
AK (Southcentral sub-region)	$7,053	$7,092	+$39 (+0.6%)
NY (Other NY sub-region)	$9,933	$10,524	+$591 (+6.0%)

IUA examples:

State	2024 IUA	2026 IUA	Change
HI HH2 (by HH size)	$11,331	$11,608	+$277
AK (Southcentral)	$7,053	$7,132	+$79

Aggregate microsim (Enhanced CPS): Utility expense variables (electricity_expense, gas_expense, etc.) are all zero in the current microdata, so the aggregate SNAP impact is near-zero. The parameters are correct and verified at the household level — the microdata gap is tracked separately.

[hua7450]

See detailed review comment above. 6 critical issues require fixes before merge: WY YAML structural error, 2 Indiana value mismatches (confirmed at 600 DPI), 5 Alaska county mapping errors (confirmed against FSP-77), and zero test coverage for the county mapping formula.