Why I am getting different slope value while performing linear regression in excel and mat lab ?

Hi, I have 58 years monthly rainfall data with size (58*12). I want to perform simple linear regression to calculate the value of slope. I am using mat lab function b= regress(Y,X). But there is difference between slope values calculated from excel and mat lab. My data set, results and mat lab code are attached. I will highly appreciate if someone can guide me whats error in my code. Regards