How to calculate and plot area under the curve using trapz or other appropriate function?!

I am trying to find and visualise the area under the curve for my data (see below) in order to compare to similar learning curve data. I have tried some ways but unsure if they are the most appropriate or have worked correctly as the data is negative and not smooth.

Any help would be much appreciated (still trying to learn the ropes with matlab).

Thanks

x y

1 -55.162559

2 -51.49817

3 -46.321619

4 -43.674017

5 -37.015529

6 -33.266756

7 -33.052172

8 -30.351532

9 -25.077227

10 -24.418889

11 -24.699318

12 -23.214323

13 -18.825947

14 -19.187909

15 -19.950888

16 -21.360635

17 -16.625949

18 -14.793957

19 -14.95093

20 -16.379339

21 -15.486643

22 -16.368055

23 -16.931243

24 -13.441767

25 -12.510163

26 -12.067308

27 -13.764358

28 -15.241232

29 -15.239815

30 -11.739023

31 -11.895491

32 -10.73586

33 -14.062533

34 -12.332744

35 -11.66472

36 -11.918313

Answer 1

[madhan ravi]

area(Y,X)
trapz(X,Y)