x=xlsread('C:\users\xy\Desktop\lgdp2.xlsx','A1:A8

it is better that you attach the excel file, so that other people could test.

the function definition is as follows:

[numericData, textData, rawData, customOutput] = xlsread(file, sheet, range, mode, customFun)

Maybe you forget to define the sheet name, try:

x=xlsread('C:\users\xy\Desktop\lgdp2.xlsx', 1, 'A1:A8');