Table:
Years Ended December 31

Black-Scholes Assumptions	2019	2018	2017

Dividend yield	4.5%	4.6%	4.1%

Expected volatility	28.3%	28.7%	27.1%

Risk-free interest rate	2.5%	2.5%	2.0%

Expected life of the option term (in years)	4.3	4.4	4.5

Tell me how many rows and columns exist in the given table. Present the final answer in a JSON format {"row_number": "m", "column_number": "n"} such as {"row_number": "2", "column_number": "3"}.

This table has 6 rows and 4 columns. Thus, the final answer is {"row_number": "6", "column_number": "4"}.