Saskatchewan taxes income in 3 provincial brackets (10.5%, 12.5%, 14.5%), with the top rate starting above $155,805. Combined with federal tax, the top marginal rate is 47.5% on taxable income over $258,482.
Saskatchewan's basic personal amount of $20,381 is the second largest in Canada. Its gap between the lowest and highest provincial rate, 4%, is the narrowest of any province or territory, so the provincial part of an RRSP deduction's value changes less with income here than anywhere else.
At $70,000 of taxable income, a $5,000 deduction saves $1,650 in Saskatchewan, which ranks 7 of 13 provinces and territories. The same deduction saves $1,858 in Nova Scotia and $1,375 in Nunavut.