The year should be divided by eight (8) to get the important periods for changes in trend.
1/8 of a year equals 6½ weeks, or 45 days
3/4 of a year equals 13 weeks, or 91 days
3/8 of a year equals 19½ weeks, or 135 to 138 days
1/2 of a year equals 26 weeks, or approximately 182 days
5/8 of a year equals 32½ weeks, or 225 to 227 days
3/4 of a year equals 39 weeks, or approximately 273 days
7/8 of a year equals 45½ weeks, or 318 days
52 weeks equals 1 year, or 264 seven-day periods
All of these periods are important to watch for a change in trend, but the most important are 13, 17, 26, 35, 39, and 52 weeks, and the same proportionate periods in the 2nd year, 3rd year, etc.