What is the change in Ms Henry's annual base salary between 2017 and 2018?
{"Mr. Dorsey": {"Annual Base Salary as of December 31, 2017": 2.75, "Annual Base Salary as of December 31, 2018": 2.75, "Percentage Increase": 0.0}, "Ms. Friar (1)": {"Annual Base Salary as of December 31, 2017": 350000.0, "Annual Base Salary as of December 31, 2018": "$N/A", "Percentage Increase": "N/A"}, "Ms. Henry": {"Annual Base Salary as of December 31, 2017": 350000.0, "Annual Base Salary as of December 31, 2018": 400000.0, "Percentage Increase": 14.0}, "Ms. Reses": {"Annual Base Salary as of December 31, 2017": 350000.0, "Annual Base Salary as of December 31, 2018": 400000.0, "Percentage Increase": 14.0}, "Ms. Whiteley (2)": {"Annual Base Salary as of December 31, 2017": 325000.0, "Annual Base Salary as of December 31, 2018": 400000.0, "Percentage Increase": 23.0}, "Mr. Daswani (3)": {"Annual Base Salary as of December 31, 2017": 280000.0, "Annual Base Salary as of December 31, 2018": 300000.0, "Percentage Increase": 7.0}, "Mr. Murphy (3)": {"Annual Base Salary as of December 31, 2017": 270000.0, "Annual Base Salary as of December 31, 2018": 295000.0, "Percentage Increase": 9.0}}
ms_henry_salary_2018 = df["Ms. Henry"]["Annual Base Salary as of December 31, 2018"]
ms_friar_salary_2017 = df["Ms. Friar (1)"]["Annual Base Salary as of December 31, 2017"]
answer = ms_henry_salary_2018 - ms_friar_salary_2017