A major source of revenue in Texas is a state sales tax on certain types of goods and services. Data are compiled and the state comptroller uses them to project future revenues for the state budget. One particular category of goods is classified as Retail Trade. Four years of quarterly data (in $millions) for one particular area of southeast Texas follow:

Quarter Year 1 Year 2 Year 3 Year 4

1 218 225 234 250

2 247 254 265 283

3 243 255 264 289

4 292 299 327 356

Compute the Q1, Q2, Q3, & Q4 forecasts for Year 5 given the fact that this data is known to be affected by:

Irregular effects

Seasonal effects

Trending effects