SN4 ""

No	Pattern	Freq
1	period of [adj] years	337
2	period [prep] [num] years	327
3	period [prep] five years	48
4	period [prep] five years	48
5	period [prep] two years	44
6	period [prep] three years	44
7	period [prep] three years	44
8	period [prep] two years	44
9	period [prep] [det] years	18
10	period [prep] ten years	17
11	period [prep] ten years	17
12	period [prep] four years	16
13	period [prep] four years	16
14	period [prep] twenty years	13
15	period [prep] twenty years	13
16	period [prep] six years	12
17	period [prep] six years	12
18	period [prep] 10 years	11
19	period [prep] 10 years	11
20	period [prep] seven years	10
21	period [prep] seven years	10
22	period [prep] several years	9
23	period [prep] several years	9
24	period [prep] 20 years	8
25	period [prep] 20 years	8
26	period [prep] 15 years	6
27	period [prep] 15 years	6
28	period [prep] many years	6
29	period [prep] many years	6
30	period [prep] fifteen years	5