[{banks:[{name:"PQR",pdf:true,amt:500},{name:"ABC",amt:300},{name:"JKL",amt:300}]},{banks:[{name:"XYZ",pdf:true,amt:450},{name:"PQR",amt:200},{name:"ABC",pdf:true,amt:600}]}]

db.collection.aggregate([{$unwind:"$banks"},{"$facet":{"pdfTrue":[{$group:{_id:"$banks.name",count:{$sum:{$cond:[{$eq:["$banks.pdf",true]},1,0]}},}}],"total":[{$group:{_id:"$banks.name",count:{"$sum":1}}},{$project:{total:"$count"}}]}},{$project:{concat:{$concatArrays:["$total","$pdfTrue"]}}},{$unwind:"$concat"},{$group:{_id:"$concat._id",values:{$mergeObjects:{count:"$concat.count",total:"$concat.total",}}}},{$project:{"_id":0,"name":"$_id","percentage":{$multiply:[{$divide:["$values.count","$values.total"]},100]}}}])