[
{
"date": "2000",
"finance": 16.6,
"physicalVolume": 193.9
},
...
]
[
{
"date": "2000",
"finance": 16.6,
"physicalVolume": 193.9,
"averagePrice": finance/physicalVolume
},
...
]
arr.map((item) => ({ ...item, averagePrice: item.finance / item.physicalVolume }));