### Package
changes from previous qlifetable version 0.0.2-4

The way grobs are defined in the method **plot** for
objects of class SAI has been modified to accomodate some changes made
in new versions of ggplot2 (>=3.5.0).

A bug in the function **annual2quaterly** has been fixed
when its input annual life table is defined using death rates (mx).

### Package
changes from previous qlifetable version 0.0.1-15

The previous version (0.0.1-15) of qlifetable just computes from
microdata the summary statistics to build quarterly life tables. This
new version includes two new sets of functions. On the one hand,
`qlifetable`

now incorporates a bunch of functions to
construct from summary statistics Seasonal-ageing indexes (SAIs) and
quarterly life tables and, on the other hand, the new version also has
new functions to estimate SAIs approximations as detailed in Pavía and
Lledó (2023) doi:10.1017/asb.2023.16.

The list of new functions includes:

**annual2quarterly**. This function allows to derive
the four quarterly life tables associated with an annual life table by
employing a set of estimated SAIs that have been obtained using either
the new function **compute_SAI** or
**SAI_shortcut_1**.

**compute_SAI**. This function computes the
seasonal-ageing index (SAIs) estimates linked to a set of quarterly
crude rates of mortality, attained using either
**crude_mx**, **crude_mx_sh2** or
**crude_mx_sh3**, corresponding to several years.

**crude_mx**. This function computes quarterly crude
rates of mortality given (i) a set of quarterly datasets of time of
expositions at risk and (ii) a dataset of quarterly deaths.

**crude_mx_sh2**. This function computes, by applying
equation (2.7) in Pavía and Lledó (2023), quarterly crude rates of
mortality given (i) a couple of integer-age stock of population datasets
and (ii) a dataset of quarterly deaths.

**crude_mx_sh3**. This function computes, by applying
equation (2.9) in Pavía and Lledó (2023), quarterly crude rates of
mortality given (i) a couple of integer-age stock of population
datasets, (ii) a dataset of quarterly deaths, (iii) a dataset of
quarterly entries and (iv) a dataset of quarterly exits.

**plot.SAI**. This function is a method for plotting
objects of the class `SAI`

attained using either the function
**compute_SAI** or **SAI_shortcut_1**.

**SAI_shortcut_1**. This function estimates a set of
SAIs by applying equation (2.5) in Pavía and Lledó (2023) given a set of
datasets of quarterly deaths.