Engel's law needs no line drawn: the poorer a household, the larger the share of its spending that goes on food. The file lets that share be computed twice — for actual spending, and for the poverty line's own basket.

year	area	food share of the line	food share of actual spending	gap
2015	PERKOTAAN	70.8%	45.1%	25.6%
2015	PERDESAAN	78.2%	55.3%	22.9%
2016	PERKOTAAN	70.9%	45.8%	25.1%
2016	PERDESAAN	78.6%	55.1%	23.6%
2017	PERKOTAAN	71.4%	47.9%	23.5%
2017	PERDESAAN	77.8%	58.3%	19.5%
2018	PERKOTAAN	71.8%	46.4%	25.4%
2018	PERDESAAN	77.3%	55.0%	22.3%
2019	PERKOTAAN	72.5%	46.4%	26.1%
2019	PERDESAAN	77.0%	54.9%	22.0%
2020	PERKOTAAN	72.7%	45.8%	26.9%
2020	PERDESAAN	76.9%	54.6%	22.3%
2021	PERKOTAAN	72.7%	46.7%	26.0%
2021	PERDESAAN	76.6%	54.8%	21.7%
2022	PERKOTAAN	72.8%	47.2%	25.6%
2022	PERDESAAN	76.1%	56.5%	19.6%

The line assumes a basket that is overwhelmingly food. No household spends like that, because a roof cannot be declined and a bus fare cannot be haggled down to rice. The gap is not drift — it has held for as long as both series exist, which makes it construction.