Need help with international accounting, please.

1. Using the information in Table 2 below, please help to calculate Transoceans effective tax rate for each of the four years (1998, 2000, 2009, 2015). Estimate the dollar amount of the annual tax reduction for the initial move to the Grand Cayman Islands. Thanks.

2. What does the result mean?

TABLE 2 Transocean Effective Tax Rate following Inversions and Conversion to Master Limited Partnership TABLE 2 Transocean Effective Tax Rate following Inversions and Conversion to Master Limited Partnership