I have to find the sample size for the information below and I am not sure how to go about doing that if someone could help me I would appreciate

I have to find the sample size for the information below and I am not sure how to go about doing that if someone could help me I would appreciate that.

The question of whether Friday the 13th is an unusually unlucky day or whether this idea is just superstition was evaluated. Researchers in the United Kingdom examined the relation between (a) numbers of traffic accidents on past Friday the 13ths versus (b) numbers of accidents occurring on Friday the 6ths (all between July 1990 and November 1992).

Friday the 6th-

139,246

134,012

137,055

133,732

123,552

121,139

128,293

124,631

124,609

117,584

Friday the 13th

138,548

132,908

136,018

131,843

121,641

118,723

125,532

120,249

122,770

117,263