Here is a detailed list of top paying google adsense keywords from financial sector. This is probably the best paying niche along with medical field. The data is obtained directly from google's tools itself. But no claims are made about the accuracy of the data, due to the volatile nature of the adwords keyword bidding.
homeowner insurance $21.96
freecreditreport $21.95
debt consolidation loan $21.79
debt managment $21.74
libor mortgages $21.58
whole life insurance $21.49
capital one credit $21.45
mortgages $21.43
life insurance $21.42
21st century insurance $21.34
christian debt consolidation $21.34
credit card applications $21.33
era mortgage $21.26
kansas loan $21.23
refinance $21.23
student loan application $21.18
debt consolidation online $21.10
nevada loan $20.90
Insurance $20.80
express credit card $20.72
21st insurance $20.68
lennox mortgage $20.67
consolidate $20.59