Period	Month	Demand	Level	Trend	Seasonal	Forecast	Error	ABS % Error	Sq. Error
1	Jan	118
2	Feb	93
3	Mar	153
4	Apr	125
5	May	102
6	Jun	141
7	Jul	113
8	Aug	99
9	Sep	180
10	Oct	162
11	Nov	122
12	Dec	181
13	Jan	170
14	Feb	143
15	Mar	185
16	Apr	195
17	May	162
18	Jun	205
19	Jul	212
20	Aug	162
21	Sep	205
22	Oct	184
23	Nov	196
24	Dec	249

ME:
MAPE:
MSE:

For the forecasting part, please use exponential smoothing with the following initalization values:

trended-seasonal=100

alpha value of 0.1