Silph Rival Gyarados survival rate by HP

At +1
HP		% to survive	Including miss
105+	84.4			84.4
104		82.2			82.6
103		77.9			79.2
102		73.6			75.8
101		67.1			70.6
100		62.7			67.0
99		56.2			61.8
-----
98		51.9			58.4
97		45.4			53.2
96		41.1			49.8
95		34.6			44.6
94		30.3			41.1
93		26.0			37.7
92		19.5			32.5
91		15.1			29.0
90		8.7				23.8
89		4.3				20.3
88-		0				16.9

At +2
HP		% to survive	Including miss
79+		84.4			84.4
78		82.2			82.6
77		75.7			77.4
76		69.2			72.2
75		62.7			67.0
74		54.1			60.2
73		47.6			55.0
72		41.1			49.8
71		34.6			44.6
70		26.0			37.7
69		19.5			32.5
68		13.0			27.3
67		6.5				22.1
66-		0				16.9