North Carolina SSP 2017, 2018, 2019

North Carolina's state supplementation payment is calculated as a standard amount established by the North Carolina General Assembly minus the federal SSI payment. For 2017–2019, the standard amounts were:
- Basic: $1,228
- Special Care Unit: $1,561

The 2011 SSA state assistance table shows these standard amounts: https://www.ssa.gov/policy/docs/progdesc/ssi_st_asst/2011/nc.html
A 2022 North Carolina DHHS document indicates that these amounts were later changed, implying that the $1,228 and $1,561 standards remained in effect during 2017–2019: https://www.ncdhhs.gov/daas042022dcdl-pna-change21822pdf-3/open#page=2

2017 state supplementation:
Basic = $493
Special Care Unit = $826

2018 state supplementation:
Basic = $478
Special Care Unit = $811

2019 state supplementation:
Basic = $457
Special Care Unit = $790

These were calculated by taking the standard amounts from above and then subtracting the federal SSI payments for each year. The federal SSI payments can be seen in this source: https://www.ssa.gov/oact/cola/SSIamts.html

Start by searching the repository for North Carolina state supplementation parameters and the tests covering SSI or state assistance. Compare the existing parameter structure with the issue's 2017–2019 Basic and Special Care Unit amounts, then add the historical values and update or add tests showing those amounts are returned for each year.

Written by the indexing model from the issue text.